Kinda depends on your drop luck though, if your first 2 legendaries from malthael are weapons, there's a good chance you can go straight into torment once you fix your toughness to not die, which is done with shitty rares with enough all resist/vit(even without OWE matching). Oh and yeah, unless they fixed it, the very first time you quest reset after RoS, you can start directly in act5. Technically would be faster to just get someone to open a TP at pandemonium though. You get 2 legendaries from malthael on a new 70char, assuming you had a full story the first time and did act5 fully, and as long as you don't care about not having any storymode waypoints until you reclear.