Considering how bitterly people complain when they feel they are forced into a particular talent or glyph due to numerical superiority, I can't agree that people don't care about having playstyle choices. If there is a glyph that increases DPS, of course people will take it — but not because they want to.
As for your last paragraph, certainly in the past glyphs had always had "best options" that pretty much everyone used. In the Mists design, however, that problem has been pretty well solved; apart from the two I mentioned, Mages are pretty much free to take what they want. Sometimes those choices will change depending on the situation. But happily, we're no longer in a situation where there are three glyphs everyone wants applied 100% of the time, and I think suggestions that we return to such a design are badly misguided.
I am not suggesting returning to anything. I am simply tired of PvP suffering so PvE can choose between shooting a Fireball or a Frost Bolt. That is the simplest way i can sum this up for you. PvErs for some reason thinks they need to have a choice between all 3 specs even if it leaves PvP with 0 enjoyable specs.