[M6 Cold vs. Phys]

For those of you who still want to run M6 for whatever reason, you should know that you are deliberately lowering your potential by 1-2 tiers, it just can't keep up with the other builds, and even for nonseason there is a stronger UE non-lightning build. Still, it has some better defensive value, mostly because your companions help you here and there and because you can kite enemies offscreen a lot easier if you can watch your sentries shooting at them from a distance, plus reflect is easier to deal with or you can hide behind a corner and still deal damage in dangerous situations.
Iceblink brings the cold Cluster build a lot closer to the physical build, to the point where they seem more or less the same. Cold has a higher luck range if you get only few and easy elites and Stonesinger, while physical should be more consistent. I guess that on 56+ the rift guardian will be a huge problem for cold, so physical might pull ahead regardless, also keep in mind that pylons used on the RG will be a lot more effective with physical. Enforcer, Gogok and BotP are still crap (7-12% worse) and if you want to play M6 on nonseason you should really stick to the Taeguk. With Iceblink, you should always use Spitfire Turret.

The best passives to use are Awareness, Ballistics, Custom Engineering, Cull the Weak, Night Stalker (5th). I strictly recommend using a Hellfire Amulet with this set because all of the passives are very strong and you don't want to miss any. Other options for the 5th passive are (in that order): Steady Aim, Single Out, Ambush, Archery.

For groups, Cluster Bombs might still have a spot if you have someone who can spawn many globes for you, but it will probably not outperform either UE fire or lightning.

My current estimate is that M6 (Cold or Phys) will clear tier 56-59 solo.

[Unhallowed Essence Fire]

All of the special bows (Windforce, Leonine, Odyssey) seem to be about on par with Calamity / Balefire and they all bring their own strengths. For Windforce, using Steady Strikers or Strongarm should be about equally strong. Leonine can shine in dense rifts with lots of slow monsters, however you probably want to use sentries to reliably proc the slow. Odyssey's End might shine at the top end (56+) because it can speed up your RG kill enormously, but will be a lot more difficult to use during the rift (since you want to use sentries for slow and use Mortal Enemy). Cluckeye only has a marginal damage bonus, but the added benefit from the stun is also nice to have.

Other than that, the 1h Crossbows seem to be the strongest options raw dmg wise. Given equal rolls, Calamity and Balefire are more or less the same, if you have fire% on your amulet Calamity wins out by a few %, also keep in mind that in groups you will buff others with Calamity as well. Also, a somewhat hidden champion might be Kridershot with Immolation Arrow + Mortal Enemy + Ess of Johan. It's behind numbers wise, but I feel that it is underrated in the spreadsheet and it could turn out to be insane if you can play it well.

In addition to Evasive Fire - Focus, Multishot - Arsenal, Preparation - Invigoration and Vault - Tumble, it seems preferable to use Companion - Bat + Vengeance - Seethe for crossbows, Bat + Marked for Death - Mortal Enemy for Bows and Caltrops - Bait the Trap + Mortal Enemy for 1h crossbows. All of the choices are pretty close (within 1-5%, except Seethe for fast weapons), so you can experiment a little. If you want to run fire in groups, Bait the Trap and Mortal Enemy should be the best for every weapon type.

For nonseason, Chakram with Spines of Seething Hatred presents a viable alternative (1-2 tiers lower than DML, and about the same level as the strongest M6 setups). I have only done the numbers for the fire Chakram, but the cold one should be more or less the same (plus you can use Iceblink instead of Polar Station). For crossbows, you can also use Chakram - Shuriken Cloud and macro it to cast automatically all the time. I have tried it manually and managed to cast it about 100 times per minute for an extra 400 hatred, in a full rift that's 6000 hatred and is more or less the same In general, for the generator-heavy builds (Chakram / Elemental Arrow), dropping all RCR in favor of better damage stats (IAS, Elite, AD) is preferred (up to 2-3% more dps per item). Chakram specifically profits a lot from the higher attack speed of one-handed crossbows, which makes it the only case where you prefer a regular 1h over a crossbow.

As for passives, the best to use are: Awareness, Cull the Weak, Ballistics, Night Stalker, Steady Aim. Ambush is also really close (about 2% behind with a 60% DML affix) and might become better because you will deal slightly more damage in reality, especially when enemies don't have much life, and you will also profit a lot more from power pylons. At the high end, it might be preferable to use Single Out because you will have to spend a lot of time on the RG.

My current estimate is that UE Fire will clear tier 57-60 solo.

[Unhallowed Essence Lightning]

It comes to no surprise that the UE Lightning build with Kridershot is a clear winner dps-wise. Due to the nature of the Ball Lightning skill it is very hard to model so the numbers are just a very rough estimation and don't take into account different monster sizes etc. I have done the numbers for a Hellfire Amulet and an Ess of Johan with equal rolls, funny enough they are basically exactly the same (0.1% difference). Since there are so many variables to it I didn't try to exactly reproduce its damage capabilities, but the numbers seem about right compared to M6 and UE fire (approximately 60-100% stronger). I have a feeling that the Ess of Johan is vastly underrated in the spreadsheet and will eventually pull ahead because you have a higher luck range and can get insane area damage procs if you manage to pull a lot of monsters. Also, this build is likely going to be one where you can see a really noticeable difference between season and nonseason because of the Iceblink gem (should be approx. 5-15% stronger). The increased potency of the slow is going to yield a lot of damage (which I calculated very conservatively) because of more ticks (on top of easier kiting), frees up another skill slot and requires you to cast a MS only once every 3.5 sec (Iceblink duration) instead of 3 sec (Taeguk duration). With Taeguk, you should use sentries to proc the slow (% chance to slow secondary on pants helps) and add Marked for Death - Contagion to it. With Iceblink, I think Rain of Vengeance - Flying Strike could be a good choice (especially with Ess of Johan), otherwise you can push the limits with Caltrops - Bait the Trap. Be aware that actually finishing a rift in time will require tremendous amounts of RNG. You will need to fish a lot of rifts to actually find one where all the stars align (good monster types, easy packs, good RG, good pylons). Since Blizzard has removed basically all of the defensive abilities this build relied on in the past, M6 and UE fire are a lot more consistent.

In high-end groups, a lot of the time will be spent on the rift guardian. Iceblink will have no more additional value because of a better slow, so what is left is solely the 10% crit chance which is a little bit underwhelming by itself. I suggest to use BotP, since you generally have a higher incentive to kill elites in group runs and will get more procs. At the high end you will spend a lot of the time on the RG, which is why you have to maximize your damage there, which makes Single Out pretty much mandatory. The 15% elite bonus from BotP is very close to a high Taeguk even without the proc. Also, you should not have higher than 55% sheet crit chance if you run with a Crusader because you will cap out at 100% (20% Judgment, 25% Single Out, 10% Bait the Trap). My numbers suggest that a high-end DH will deal approximately 15-25 billion dps on a typical RG.

The best passives to use are Awareness, Cull the Weak, Steady Aim, Single Out, Ambush (5th).

My current estimate is that UE Lightning will clear tier 60-62 solo.

[Natalya]

Unfortunately I couldn't include the Natalya set in the spreadsheet, the most important reason being that we don't even have a finalized build for it yet. In the last couple of days people have made huge progress (up to tier 55), so there are some good builds already, however I think there is still a lot to discover and that some of the set's potential is still unused. I'm very excited to try it out myself once I can start pushing solo, I have lots of ideas that want to be tested. For now, it's best to just keep all of your good Natalya pieces and anything that might go with it.

However, I can still state what there is to know about Natalya currently: F+R seem preferable. Strafe + a generator is very good to reduce the cooldown of Rain of Vengeance, you can hold down your force attack button, keep strafing and hit your generator button manually whenever you can. Cooldown is a very strong stat, a lot stronger than e.g. RCR for other builds. N6 works for any damage including gems and conduit pylon, both N4 and N6 are multiplicative bonuses and also work for your Crashing Rain belt. The belt summons a crashing beast (very short visual effect) with a small AoE effect that looks similar to one of the Stampede rune at the position of your cursor and uses the same element as your selected RoV rune. Both Crashing Rain and RoV (and Fan of Knives) use only your main hand (left weapon slot), so you don't need %damage (or any damage roll at all if you don't care about generator / Strafe damage) on your offhand.

My current estimate is that Natalya will clear tier 57-62 solo.

[Reroll preferences]

Here is some general information about what you look for on your items (if it hasn't been specified before already).
Generally, you get RCR on every item you can, excluding jewelry, and add area damage on shoulders.
On rings, Avg Dmg instead of CC or dexterity is about 4-5% weaker on crossbows and up to 1-4% better on 1h crossbows, and more or less the same for bows. Keep in mind that in parties you will probably cap crit chance on the RG with Single Out, Bait the Trap and Judgment. RCR is also an option for crossbows (1-2% weaker).
For the UE builds you can basically drop any CDR because it is almost useless. Only take it if you want to go full glass cannon (and even then having some more toughness might be helpful for Plagued and Desecrator). Removing all of the CDR (gem, paragon, shoulders) is a 1-2% dmg loss with Bat Companion, 3-4% if you use both Bat Companion and Seethe. I recommend to drop it completely if you use MfD and Caltrops.
Elemental damage is better than dexterity or CC on amulet, up to 5-10%. Probably even a 15% roll is preferable. Ancient dex value might be close.
IAS instead of RCR is an option for 1h crossbows (1-2% weaker) and preferred for Kridershot and Spines of Seething Hatred.
Dropping Multishot damage on quiver for hatred / elite / area damage is a 3-6% damage loss. Dropping RCR for hatred is a 0.5-2% damage loss (keep in mind you can vault more with RCR).
Steady Strikers / Lacuni Prowlers can be better than Reaper's Wraps if you don't get many globes.
For UE lightning, I recommend elite bonus as your last primary, especially for groups. Area damage is fine as well.

Добър пост. Ма ме заболя главата!