I miss the days of frost being survival for pvp and leveling for pve (thanks to frostbolt freezing stuff) with arcane and fire being for pvp kiting and pve raiding.

Arcane PvE is actually quite strong, despite what most people think. Once you start seeing a few 372 items, arcane surpasses fire for single target damage.

Ok Christian/Readers here is some food for thought, what if they made the frost tree much larger...the idea I have would require the tree to be about doubled in size. now, im going to use two concepts here, one in Rift and one already in WoW to some degree. This would require a large overhaul of the spec, not so much in talents but in the way the tree is designed.
Deep breath, wall of text inc.

Concept:
a). Make two separate sections of the frost tree, one side valuable to pvp and one valuable to pve. The way the two trees would work is thus: Talent A is required for talent B which is required for C which splits off into D and E which are required for X and Y and so on. This way to get the valuable talents for lets say pvp you have to go so deep into the PvP side it is no longer worth it to tap into the PvE side, and put the talents that would be valuable for PvP but are meant for PvE so deep enough into the PvE side that they are inaccessible to those going into the PvP side. Im not talking Deep Freeze or anything here, those talents could be perhaps duplicated in both trees, im mainly talking about talents that "increase damage by X" or "Increases critical strike chance of Y by X"
This would allow both sides to be balanced differently.

b). Make talents in this PvP "side" of the spec "Increases damage against PLAYERS by X" or "absorbs X amount of incoming PLAYER damage". Therefore it would make talents in this spec unattractive to the other side intended for PvE because it would be a 0% increase in PvE.

Anyhow tell me your thoughts, I know theres alot of room for improvement but this is my basic idea.