I am old school.. i dont feel like spells should be treated like other combat abilities.. it should have its own mechanic. Love the idea of a mana pool magic pool whatever.. with a GCD of whatever is standard.. 1.5 seconds as an example. also I feel like you can have say any spells on a hotbar up to say 5 at low levels 10 higher etc.. and you can not change them unless you visit an inn. Takes time to memorize all those arcane magics

I feel in this way there could be more mages or spell casters neeeded in a raid.. instead of just a few.. since you can only bring a certain number of spells.. also have a spell set for farming monsters.. gathering resources.. pvp.. etc. Makes you value your spells and maybe takes a little though into what you want to bring for any given situation.
just a thought didnt say it was a good one.. but I like it