If only someone could come up with a system that still gives Wizards a few, big, powerful, daily spells, some solid ones that could be re-prep'd after a quick rest and component/study prep and even a couple of baseline spells they could use at any time. Then, even when you've blown your big guns you have some pretty good spells to fall back on and don't have to resort to throwing darts or missing with a crossbow. That would be awesome.
Yeah, too bad no one has implemented such a system in a way, that feels like D&D casters.
The system of 4e comes close to that goal, but it needs to unify rituals with spells. And only 1 daily spell available per level, chosen fro 2 does not evoke the right feel.
If you had encounters and at-wills, but a big list of dailies, from which you could chose some more as you need, it could work. The implementation as it stands in 4e. No. You usually prepare the same spells over and over again. No strategically chosing, because you usually don´t have the tools fitting for the situation:
Fireball in narrow halls? No. Prepare lighning bot instead. Such things are really missed. But it is not all 4e´s fault. The bard in 3.x and the sorcerer also fail in that regard. I don´t mind, if there is a class, or even 2 kinds of wizards in next. But vancian magic is one of those things I really would miss if it was thrown out.
One thing I could live would be a system similar to spells&magic spellpoints, which bring a lot of flexibility by being allowed to memorize free spells of a level.
So my favourite wizard:
minor at-will cantrips
some encounter like abilities along the lines of 5e magic missile or 4e shield (or at-wills that need components)
vancian dailies that can turn the tide of battle
some spontaneously castable spells in some fashion