I'm maining WW but looking to reroll for 7.2 as I don't like the direction the spec is going (more resource starved). I've played my 90ish sub rogue a bit recently, and it's fun: it feels like I have a lot of energy/cp to play with, the animations are cool, seems there's some depth, and rogue is a bit appealing as it's pretty much the only melee that's desired by guilds/raids. On the other hand, Outlaw is the least appealing spec in the game to me (rng) and Assassination seems very energy starved and kinda simple.
I haven't heard much of sub in Legion, Preach gave it a pretty negative preview and most of the sub rogue stuff on youtube seems to be PvP-oriented. Is it fun? Are sub players happy? And very important to me; are there any big frustrations with the spec? For example, as a WW, sometimes our clones don't copy our big spenders and we do less dps than we would normally despite using CDs which is incredibly frustrating.