I haven't finished a single playthrough yet for several reasons, some of them technical e.g. a patch killed all my saves, or abyssmal performance in act 3. With patch 5 everything runs good enough that I might actually finish the game. Yet I struggle, part of it is the length of act 3, which might be good news for you. I need around 45h for act 1 and act 2, because I'm a completionist. When I arrive in act 3, I'm already exhausted and from the way the quests start coming in, I assume, act 3 will be another 45h. Currently I'm sitting at around 60h and have only done sorcerous sundries, Shadowhearts quest, some exploration, digging a bit into Laezels quest.