Conquest mode is my favorite because of the passive bonuses you get. The problem is that sometimes the final battle is so unsatisfying. It's randomly selected so it sometimes gives a completely stupid battle that doesn't let you really make use of the passives. I also wish I could pick passives for fun in a by myself game custom game. I'd be fine with not getting achievements. That way I could remake my own glorious finish to a conquest with all the passives I did earn. It can just be really unsatisfying. Also, sometimes they will patch things without warning that are actually large changes to gameplay.