Sounds like Sorc is the answer. But why not a Breton? I envision a buffed-up Merlin-kinda guy. But not a fan of the pets.
There are 2 trade-offs you need to consider when making the choice between Altmer and Breton. The first is the classic trade off between Damage and Defense. Altmers get a boost to all elemental damage, which is perfect for sorcs because basically all the damage is elemental. Bretons get spell resistance. Nice, but a min/maxer would never pick the later. The other trade off is a little less clear. It is the trade off between magic cost reduction (breton) and magic recovery (Altmer). The classic school of thought was the reduction was better, but with enough CP, it seems to no longer be the case. This choice is splitting hairs if you ask me. Dark Elves are in third place IMO for a sorc. Sorcs just dont do a lot of fire damage, and dunmers get less magic then the other two, so less overall damage. Now for a magic DK, they are the clear favorite.
Nothing wrong with Breton. My Templar is a Breton and he looks like Gandalf. Haha.
Altmer is the only race that gives bonus to all elemental damage, meanwhile Bretons have decent passives for max magicka they do not have any passives that benefits elemental damage.
Sorcers mainly use elemental damage, and have a lot of passives for boosting shock damage - so Altmer is by far the best choice for this class.
For endgame pve = Altmer because of elemental damage bonus.
For veteran pvp = Breton because of their high spell resistance.