Something else that I think is a pretty huge issues for end game casters is...
Lack of Focus Effect progression at T12-13
I made a thread detailing this odd problem a while ago, but now is as good a time as any to readdress it. Focus Effects are the main way that spell casters get more powerful through the game. Through raid tiers 1-11, there is a focus effect gained, on average, every 1.5 tiers. At the most, you might go two tiers, before you have the next level of focus effects. Focus 8s are available in T9, more available in T10, and by T11, nobody has any issue wearing all Focus 8s. If normal progression continued, even by conservative estimates, we would expect to see focus 9s start to show up in T12, and be pretty widely available by T13, but this is not the case, we just keep seeing more and more and more Focus 8s. This means that from T10-11 on, casters kind of stop progressing. They get small gains to hit points and mana, and maybe they get a cool clicky effect or something, or some tomes, but their ability to cast damaging spells, or healing spells doesn't improve as it did through the rest of the raid game. T13 yields a grand total of ONE Focus 9, and the bits and pieces of T14 that have been seen still seem to have Focus 8s. For a while there was a workaround to this problem using channeling, and some other unique/odd effects. Channeling granted more spell crits, the 4.3 robe granted CSI 10, the 4.3 sword granted DI 10, but all of those have been removed from the game (or in the case of the sword, just made unusable).
Since all those weird effects, and channeling were deemed bad ideas (and I don't think people are really arguing that point) can we please go back to the old, tried and true, method of caster progression and give new Focus effects? Focus 9s should start showing up in T12, and be pretty widely available in T13, and T14 should really be the beginning of focus 10s.
I really hope this can get resolved, because the nerfs to channeling and 4.3 gear dropped my characters effectiveness by ~15%, and I have yet to regain any of that. Focus effects are the proper way of allocating that power, and I really hope the powers that be will recognize this and re-itemize some stuff to fix the issue, because right now playing a caster or healer is really boring when it comes to gear progression.