a1 with Overawe + Blazing Wrath + Faith in the Light + Thunderclap= the only way to do it. A2 is just WAY too gay, no matter how much gear you have something always comes along that fucks you big time.

0 deaths, first fucking attempt, still a super intense fight though that was super close at times. Only reason didn't have 5 stacks for Diablo is because I fought an extra health mob with like 10 trillion hp that took 15 mins to kill and he died literally the second NV expired.

Anyways, after face tanking 95% of the packs in inferno, I would have to say the hardest part of the entire game was the Arreat Core 1/2 in A3, and the hardest boss was undoubtedly Larder. Diablo was tough but was more of an endurance "dont fuck up" fight, Larder you just had to get lucky.

A4 is really only tough if you hit a molten pack close to the start of a level and cant kite, otherwise theres a lot of room for ranged to kite and melee to facetank a couple off to the side.