I doubt there would ever be a time when this forum wouldn’t be full of people moaning about thier spec being under powered in their favourite aspect of the game but I think it has to be that way. It’s not just the complications of balancing every spec in every aspect of the game it’s that it would make it boring.
What if written there on the specialization screen it told you where that spec excels. It would make it easier for players to choose a spec and easier for players to understand why their spec isn’t preforming well in a certain situation. It would also help developers keep specs consistant.
Raid: Below average single target damage but excellent 2 target cleave damage. Brings group utility in arcane intellect and timewarp.
Dungeons: Strong area of effect damage and AoE slows, aswell as strong crowd control with polynorph. Below average single target damage. Brings group utilty with conjure food, arcane intellect and timewarp.
PvP: Very strong at control over melee with roots and slows and good burst damage. Has a strong cc in polymorph. Brings group utilty with conjure food, arcane intellect.
You let the world know what the spec is about then with any tweaks or changes you make sure the spec keeps its personality.