mages are unbalanced

{quoted}

Even though I'm not ranked or anything my insight is:

1. Mana Issues (If they were forced to rely on their abilities all the time, mana would run out really quick)
2. It really helps to CS because its just single target and some spells are aoe so that affects other minions too.
3. You would have to wait for cooldowns if you use all your spells and meanwhile, the minions would kill eachother.

pretty much this. you need to be able to CS and you can't do that with only ONE ability that has a COOLDOWN and costs MANA(or an alternative resource for some champs) therefore they need AD to be able to at least last-hit minions without blowing their entire mana pool on the first wave and without falling behind other champs like marksmen or zed, talon, etc that will be able to cs without much trouble if that were the case. Obviously once you start putting together your first good AP item you will start to be able to farm with abilities as a mage and won't rely on auto attacks so much unless you're doing something like controlling the wave or trying to not push it obviously.