Spellcasting is a lot to lose... I'll try to think of some options:
A) Alchemist's Bombs (cha-based instead of int-based) and Discoveries (likewise) including the higher level versions
B) Summoner's Eidolon, free Extra Performance feat every 4 levels, and Inquisitor's Solo Tactics and bonus tactical feats
C) Full BAB, d10 HD, proficiency with medium armor and shields and all martial weapons, and Ranger's Combat Style feats
D) Witch's Hexes (cha-based instead of int-based) including major and grand hexes at higher levels and Rogue's talents including advanced talents. Make the talents come at levels 1, 3, 5, etc... so they're not hitting the same level as the hexes.
Just some ideas, not sure if they're that balanced, either in terms of being over- OR under-powered.