My gut reaction is that's a lot harder to balance than you might think. In the traditional D&D system, even though the casters are getting more and more spell slots they can cast, there are always a limited number of the newest high level spells while plenty of other slots are populated by spells of smaller scope and power.
Cut the number of spell slots but migrate them into higher levels and you'll probably get a higher number of spells overall at the highest level of power. For example, if you limit the caster to 10 slots but move them up a spell level every time a new level becomes available, suddenly you have a PC with 10 9th level spells as soon as he qualifies for them. In the old system, he'd have a lot more spells but only 1 9th level spell on top of 2 8th, 3 7th, and so on. And don't even try to balance the play styles between the power gamer filling them all up with the highest level spells he can and the more moderate player who takes a 1st level charm person so he can charm his way past single gatekeepers and get what he wants.