For healing you could make it be more like using herbs and poultices (you could maybe try and make the healing run of skill or something), and for class variety use the 3 magic ranks you now have free for additional physical weapons, maybe a simple weapons category with like slings clubs and daggers, a polearm category and for the 3rd i cant think of one of the top of my head.
edit: to add utility to archers you could make them effective against armored units because arrows can pierce armor (with a good angle the proper arrow)
also i seem to recall a patch that let units have weapon ranks in both magic and str based weapons but they ran of the same stat, if you can find it a patch without magic would be a good place to use it
edit 2: it occurred to me that you would likely need asm to make the second set target defense not resistance