Since Mages still could do with improvement, I've kept up most of these ideas. One of the specs is dull, the other very gear-dependent and a rollercoaster in how much fun it is, leaving just frost. So, I'm putting forward some suggestions (mostly a collation of mine and others) for arcane:
-Modify PoM to be like Chakra, and put it on a 30 - 45 sec CD. See more below.
-Mage Ward/Mana Shield. Give arcane a talent modification to expand the number of schools the former affects and reduce the latter's mana inefficiency. Possibly allow it to have an on-going effect, like TFT version. The downside is your mana evaporating.
-Relatedly, remove Mana Shield from CD, and instead place an ICD on the Knockback effect. Increase/decrease as needed.
-Bring back a buff effect like Pushing the Limits! It need not be haste, though that said it did make arcane a lot more interactive to have to try fit in an optimal spell sequence under the buff. See more below.
-Some interrupt protection. Possibly a talent to replace Burning Soul, instead making Pushback protection (as with all casters), baseline. An idea was to let interrupts confer an 8 second long 10/20% DR for when locked out from arcane (particularly crippling for this spec) as a talent.
-Cosmetic one, but give Arcane Blast a better/more obvious animation.
This should give the arcane Mage more of a feel like a manipulator of time and space, as well as Nether energies. Right now, the talent tree is dull, poorly thought out and the execution similarly bad. There's little real control over mana other than just using Mana Gem and Evocation on CD. The ideas for PoM are just for example's sake. They could be anything. I just liked those in particular. Some people might say this is too much like Soul Burn, but that spell is a minor factor in the Warlock priority list, and with ISF mechanics being reworked, probably even smaller in the future. Arcane needs some spice anyway. Warlock priorities don't.
For POM: A genuine Chakra effect.
-Use it with Arcane Missiles (leaving the next 2 - 3 spells free), and you enter a mana conservation phase, whereby Arcane Missiles is affected by Arcane Blast and gives a haste buff, and Arcane Barrage gains a small mana-burning dot (if made baseline, this dot grows in power under this effect.) This will let it synergise with Dark Intent.
-Use it in conjunction with Arcane Blast (firing off a ramped up, high damage one as a bonus), and you enter mana-burning rotations, whereby Arcane Barrage benefits from Arcane Blast (and also costs more in proportion with it) and rises in power as your mana depletes (so you use it after a breaking point of Arcane Blast spam.) In this phase, each Arcane Blast should add to cast time but rather than a 10% baseline ramp up it should be 15%, whereas the mana conservative phase should remain at 10% but reduce cast-time, possibly avoiding it being OTT in PVP.
-It could also work with Arcane Barrage for mobility phases, protecting Evocation from pushback, lowering Arcane Barrage's CD by a sec and giving it and Arcane Missiles a damage buff proportional to movement when used, but conferring no big DPM or DPS advantages like the other two PoM effects. It would also let Arcane Missiles channel whilst moving. During this phase, Arcane Barrage could stun when it crits with a 10 sec ICD, probably replacing Improved Polymorph; otherwise sharing DR. It could also be used to extend the Arcane Blast debuff, like Fel Flame does Immolate.
-Use it with Flame Orb (it gains the Gravity Well effect), and your Arcane Missiles and Arcane Barrage gain a volley effect, but you also become vulnerable to damage yourself and/or suffer a movement slow debuff. Should limit abuse in PVP.
This should produce a marked difference for arcane between the burn phase and conservative rotations, and give it something to do on the move and when AoEing.
If Evocation/Mage Armor/Frost Armor become too good, reduce mana returns to even the spec out. Alternatively, if Blizzard wants Mage Armor to be used, force it being up to enjoy the mana burning dot on Arcane Barrage and the siphoning effect on FO.
-Either bring down Combustion's CD to 1 min and apply nerfs where appropriate elsewhere, or allow Fireball/FO/Scorch to lower its CD in an RNG manner, like Shadow Bolt/HoG does with Metamorphosis. A lot of the fun in fire surrounds this CD.
-Put FO on a lower CD for fire so it factors in more rotationally. 30 - 45 sec.
-Possibly give Blazing Speed a modification to Blink that leaves a trailing blaze, like the elementals in Twilight Highlands. Give it high enough damage and width so that anyone trying to immediately follow the Mage gets singed.
-Give Fireball the old Pyroblast effect. It just looks weak, which isn't a surprise since it looks like the Imp's firebolt.
-Restore some dispel protection to Living Bomb, and for Combustion. Too much of this spec's damage output can be reduced in this manner.
-Change pyroblast to have 1.5 sec cast time, 6 sec cooldown (hot streak would still make it free and not cause a cooldown to start) and add it to Firestarter. (suggestion from Plumbum on Mage forum) If such a mechanic isn't implemented, let Hot Streaks stack to 2 - 3 (like FoF stacks to 2.)
-I'd like one of those new water Elementals to replace our current one's model. A few more options for keeping the elemental alive would be cool but not a huge priority.
-Frost has mostly been brought into balance, so I don't have much to say about it. It's still very dispel sensitive, but overall a good spec. I'd like for more casting rather than instant usage, but considering that that is an invitation to be interrupted, it can only come with a re-evaluation of interrupts and casting in the game.
-Make FM baseline.
-With Time Warp being even more situational, it possibly needs to be made a lower level spell and a new 85 spell to replace it, obviously in the arcane school. Could even be FM, per someone else's suggestion, and that would have the effect of making it baseline. Let TW at least affect arcane Mages individually to make up for the loss of IV.
-Not related to Mages specifically, but put Interrupts on DR. They're too effective for the number of them flying about right now not to share it. Something like Rift's location check only being enforced at the beginning of casts would also be cool, so melee can't just exploit the lack of realistic physics to run through to avoid spells being cast.
Feel free to add/criticise. Just don't come with "lol stay lock then", since I could obviously do that, but that doesn't do a thing to make Mages any the more appealing a class. Numbers and so on could be tweaked as needed.