Every class in 2.1 is going to have like a dozens of build that will be T6 viable. At this point the balancing and benchmark from "how does this perform on T6" to "how does this perform at GR 30-40".
Yeah, I was pretty much typing the same thing in response to the guy that asked about build diversity.
It really does just depend on what you want to achieve. Even in the current game (pre-2.1) there is a boat load of different builds people play, it's just most of those cap out at around Torment 4. That's obviously a problem for a lot of people because they want to reach Torment 6, trying to do that limits what builds you can use....
Until 2.1 anyway. As Dahbomb says there is going to be a ton of T6 viable builds in 2.1, this is from Blizzard buffing nearly every skill in the game and changing a lot of items to make them better. But then the new problem will be "This build can do T6, but, it can't do Greater Rift 40" so reaching that point will again limit build diversity in some way.
However... This is a better problem to have, because the only reasons to reach higher Greater Rift ranks is for leaderboard purposes and upgrading your legendary gem. Leaderboards are whatever which only leaves the legendary gems, going up ranks makes it easier to upgrade them, but, it's not impossible if you aren't reaching the highest ranks. Also I do believe the most recent PTR patch made it way easier to rank up the gems to where you unlock their second ability (which is probably the most important part of the gem process anyway).
