I had an idea and was wondering what people thought of it.
First everybody gains 1 feat at every level. (plus bonus feats for classes that get them).
However, spellcasters must buy thier next spell level with a feat.
For example, consider the cleric.
the feats would be;
Cleric Spells I (prerequiste cleric level 1) - grants access to first level cleric spells.
Cleric Spells II (prerequiste cleric level 3, Cleric Spells I) - grants access to 2nd level cleric spells.
As you can see, you can't skip spell levels you have to take them in order.
I thought of this because A) learning spells is supposed to be hard and B) to address the LFQW issue a bit.
A new spell level is stronger than any feat I can think of. This is roughly equivalent to "spellcasters get no feats" ('til late in the game).