ToA was used for class-balancing which was a good or bad thing depending on your viewpoint class & ability to complete ToA. Even that has been balanced out now somewhat by recent patches.
Some classes are better than others in post-L50 RvR. Some classes are awesome fun in the lower BGs but don't get a look-in later. Some classes excel at PvE but are largely unwanted in RvR. Most classes I find fun to play in the context in which they do well, it's just a question of picking your classes according to your temperament & what you want to achieve.
Perfect class-balance is an unachievable illusion.
I think you have to take a long-term view in a MMORPG, & on the whole I think Mythic have done a pretty good job apart from the huge hiccup with ToA, & in retrospect I even really like ToA (especially now they're making it easier for gimps like me
