I hope they find a way to keep rogues happy while making the class more enjoyable to play against, but I really doubt it's possible for both to happen.
I think that is really the biggest issue here combined with some other smaller ones. What about sub makes you think "shadow ninja" right now other than shadow dance? Rogue has always been the least represented class in the census' over the years even during their cata domination. The class basically has no flavor or fantasy right now and I think the changes they're making are really exciting. Rogues/hunters kind of fell into the trap where there was very little way to distinguish one spec from another for newer players fantasy wise, and I think people on this forum have been playing the game so long they're just scared to see such a large change.
One of the things I miss most about vanilla/tbc was the sense of identity or even "server fame," if you will. I remember seeing players run by and recognizing them solely because they had a reputation for being the best spec/class/gear on the server. They need to bring those kinds of things back, I think most specs should have a level of complexity that are very easy to learn but extremely hard to master ie sub rogue.