The spellcasting feats are... rough around the edges, yes. I think ultimately it would be a good idea to try to unify the feat progressions for all spellcasting styles (as an added bonus, this should help condense a few near-duplicate feat entries). Currently, spontaneous spellcasting builds spell lists by level and prepared spellcasting builds spell lists by groups (schools/domains); I think it might be a good idea to have all spellcasting progressions run off of a combination of both. This would allow some of the feat costs of spellcasting to be shifted to higher levels, keeping spellcasters from being so nerfed at low levels. Plus it would help modularize the design, so it should in theory be easier to add flexibility without needing to write up lots of redundant feats for different lists/casting styles.