Who to rank up? (Please help)

CaptThunder

Please tell me who I should rank up in order to go through act 6. If you could also explain why in the comments, that would be much appreciated. Thanks.

Ortoun

Diablo, especially if you run MD is a real workhorse. Being able to heal off the sp1 makes it a lot easier to end fights at higher health, lowering how many potions and revives you might need. He has fairly decent utility, but you only need to choose the parts you need, the rest shortens his ramp up. I do recommend using his synergy that makes his mix pause during his specials, as it makes it a lot easier to keep all his good utilities active.