[MaxWilson]

I have seen the behavior you describe (mage targetting lone commander instead of group of infantry) in recent patches as well. I think it started at the point when the game was patched so that LoS would not be cast multiple times on the same group of units. I have not played around much with tactics--up to this point I've just done as you have and put the mage in the middle--but I think I'd try mixing in some low-prot units in the same squad as the high-prot ones you want buffed.

-Max