The pattern 3 expansions running -- including this one now -- is for it to suck at the beginning, get better and better as crit rating goes up...and then at the very end of the expansion cycle blow up and go nuts.
It's a bit like what happens to warrior with rage. (Or used to. Maybe rage has been tamed this time around.) Scaling is NOT smooth.
And, yes, the biggest problem the class has right now is the level 90 talents and more generally speaking lack of polish. The class was dialed in this time around and needs some fundamental changes and fresh thinking. Mage design is aging badly and due for a revamp of the sort that was done to warlocks.
That won't happen until the next expansion. They flatly ignored all the warning signs in Beta. At best, you can expect QoL changes. Nothing more. Then, two years from now, when mages still hate these talents, maybe they will consider doing it all over again and get it right.