yeah mages are pretty crazy right now, I do agree. I do find it strange that nobody every complains about shadow priests, they've got nothing but straight damage buffs this patch.
Of course you are more qualified than me to critique but those are my thoughts on every class on the PTR:
Death knights: Very strong damage and insanely good versus priests - they need a slight damage nerf
Druid: Druids are somewhat balanced (feral/resto). On the other hand boomkins are disgusting - they take way too much damage but with procs they can gib you in a millisecond. 150k starsurges on 67% resilience is the norm
Hunters: They do too much damage - BM is an abomination of a spec, and while super strong, any decent team that will swap and gib the pets removes most of their strengths
Mages: Most op class on the ptr - now frostbolt does tons of damage too. Fire is disgusting (Affx will still defend it). Way, way too many instants
Monks: Imo the most well designed class out there - mistweaver needs a nerf in dematerialize and windwalker could use a 5% damage nerf and a slight buff in survivability. Ring of peace could stay as is BUT with a reduced radii (about 30%)
Paladins: Rets are quite nice with the new buffs and certainly in better shape than on live - holy is still a very strong healing spec, on par with resto shamans and druids
Priest: Shadow could use a slight damage nerf and it would be perfectly fine - disc shield buff was uncalled for and it dragged them from being on par with the other healers to being the strongest one (although heavily countered by dks)
Rogues: Too much utility and strong damage and defense vs casters, but they flop over and die vs any melee from dks to warriors. Some passive melee damage reduction coupled with a slight nerf to feint (~5%) could put them in a decent place.
Shamans: Resto is cool and on par with the other healers - enh is definitely viable - ele is a paradigm for all caster classes right now since they are the only dps caster to actually cast (and does gr8 damage while casting)
Warlocks: The affliction playstyle is simply an aberration - soul burn swap and dot the whole team is unbelievable cheese-y and has no place in arena. Other than this gimmicky ability they are average and they could use a hefty dot damage buff under the condition that they have to cast to get dots up - while at it remove soul shard requirement from haunt which is ridonculous
Warriors: Way way way too high damage - if you manage to master the new rotation (which is not easy) the damage output is almost unhealable. Utility is somewhat limited now with the shockwave nerf. It feels like the start of s6 (with 12 sec charge and intercept) with even more damage. Only problem is that we die almost as fast as rogues which is could because now you have to watch out for your positioning.