MoonSong
Rules-lawyering drama queen but not a munchkin
Well, for starters Clerics have less slots than the wizard, and an overall more focussed spell list with far less niche-invading spells, and they need the tactical flexibility in order to be good battlefield healers, otherwise they would have to preppare only healing spells, and second it fits with the flavor of the class. It sure should be painful to play a blaster wizard, I don't feel like I could run one, the only wizard I've ever played was a diviner, but it is the cost for knowing an unlimited number of spells and having the ability to switch niches overnight, that oppossed to sorcerers and warlocks that are stuck within a niche for their whole careers, tactical flexibility and wearing armor are what keeps them more or less competitive compared with wizards, giving those to the wizards is like taking away a kid's very treassured special plushie to give it to the spoiled kid that already has more toys than he can play with on all of his childhood.I disagree. Preparation is a big enough limit, I don't think it's necessary to have to guess how many fireballs I might need on any given day. If it doesn't break the cleric, I don't see why it would break the wizard.
Just to clarify, I would remove the restriction from casting spells in armor, but I wouldn't give wizards any armor proficiencies by default. Some traditions, like warmages, might have that option, though.