@
Firefall: Please don't make up stuff when it is so easy to counter it. For example the first 13 specs on Mythic Garothi are melee specs, so while you are right that there is an "imbalance" that you need a certain number of ranged classes to ensure melee classes aren't targetted, you are dead wrong in claiming there is no downside to only having ranged (as in you loose a butload of dps).
But this isn't a discussion about melee
On solo'ing, playing a mage is kinda a downer compared to a melee. This is a well known fact and the reason why for example elemental shaman primarily levelled as enhancement. Luckily there are almost always groups for WQ's and there is the Warframe on Argus when there aren't.
For the next expansion it will likely be more difficult as a mage to level/quests/do anything compared to your other classes (except get a raidspot
). You should make the choice of class depending on what you will be doing most. If this is dungeoning and raiding then there is no problem with playing a mage. If you will do mostly solo content, you will likely prefer playing any other dps class (with the possible exceptions of shaman and priest).
Can't comment on pvp as I haven't done any since TBC.