I'd been purposely avoiding all info about Act 4, hadn't touched the game in several months. Fired up my level 81 Incinerate Witch on standard just to play through Act 4 Merciless and check it out.
Re-distributing my skill points, I pretty much followed my old build but it seems like I ended up with a lot less mana(I have a pre-nerf Cloak of Defiance, so mana pool for soaking damage is big for my build), but I think a lot of that was the change to Arctic Armor, reserving 20% now rather than just a constant drain(and damnit, I had the regen to cover the drain, even when moving, oh well). With Herald of Thunder, Ice, clarity, and arctic armor I only had about 300 mana left for my CoD/Mind over Matter damage absorption...that kinda sucked
Anyways, I thought the act was really well done, although I expected it to be a bit longer, it seems much shorter than the other acts.
Most of the bosses seemed to be well balanced and pretty straightforward. The only two that seemed ridiculous were the new Piety(are you just supposed to run in circles constantly to avoid that damn beam or what?) Sucks for classes that need to stand still do DPS (like my Incinerate). I don't remember the name, but when you're collecting the 3 Malachai body parts from the mini-bosses, the 1 mini-boss thats like all physical damage/EK with the mines on the ground, that shit was ridiculous. As someone who relies mostly on their arctic armor + life leech for defense, that physical damage rocked my world. I died like 5 times to that goddamned mini boss. More deaths than even all the phases of Malachai at the end combined(I died to him once until I figured out what was going on).
I can't imagine getting through the new piety and that physical mini-boss on a hardcore league, at least not without porting to town a half dozen times(which always feels like a really cheap mechanic to me, I hate to have to rely on that)
Also note that while I went into all of these fights totally blind with no knowledge of them, I was using a vastly over-leveled character that could put out about 25,000 DPS with my (phase 3)incinerate