Since I’m close to finishing my retaliation char, I decided to take a shot at actually finishing the Trial of Ancients. So here’s my feedback.
The mob difficulty seems to ramp up very hard at a certain point. Like you’re going from fighting one act boss and some trash mobs to going up against 2-3 WB and then 2-3 ubers over a rather short span. This makes the beginning kind of boring and the middle maybe a bit too difficult I think. The last couple of stages were evenly paced, no complaints there.
Still, I’m wondering how a non-max block/max evade build is supposed to deal with 4 supercharged wb/ubers at the same time. The arena is tiny, mobs aggro no matter where you stand and there is little to no cover to catch your breath. To me it seems like you need a super-defensive build, cause superior strategy isn’t going to get you anywhere in there. Compare that to the old Shattered Realm arenas, where you normally had the means to break line of sight for a second. Here you can only run around in a circle.
Some of the council member mobs seem to have a completely unreasonable amount of defense. For those my chance to hit showed as 60%, whereas for uber(!) baal it was at 135%. Why would a normal boss mob have probably twice the defense of the final boss, that must be a bug, right?

I really like it for getting the last levels to 100, those are a terrible slog in normal open world grind. Also nice for maxing devotion abilities. But I gotta say, the reward chests are nothing to write home about. I did the whole trial from start to finish in one go and got 5(?) chests which didn’t contain anything I couldn’t also get from a random WB (which takes 30 sec in comparison). Not a single unique component, no high-level rune, just some random uniques I’d never consider to use. For the time invested I think the rewards should be much better. Your char is probably finished anyway by that point, might as well give out some proper stuff.
Also, what’s the fastest way to get trial factions points? For the whole run I got maybe around 300 points, that seems very little and will probably take many, many of these to get to tier 3, even with writs. I’m eyeing a certain augment, but I can’t see myself doing this ad nauseam just for that.