Buying idols (minus priests early game) seems pretty much useless UNLESS you are using them as fodder while your queen attacks a tower. In Many levels the idols/summons will be destroyed within seconds due to aoe damage etc. One can purchase additional health/armour for  minions, or invest in the awful +50hp skills, but i think there should be another option.

I know the developers do not wish to change the way summons work. So, how about a purchaseable item and/or favor item that gives magic resistance ONLY to your summons? This would prevent them from being to over powered in a melee fight while still allowing them to be somewhat useful in a 3vs3 pileup. If groundspike etc doesnt completely murder your guys perhaps spending the money on idols and investing in yetis or shamblers might make sense?

Im not sure what the percentage should be. Maybe a max of 50% magic resistance if more than one items are combined would be appropriate for late game? More even makes sense to me. Generals were not ment to rush into the middle of a fight in crucible...but since thier minions die in 3 seconds the general heros are forced to. Even 75% immunity by late game would be viable.

ALSO, an new idol that sold a magic resistance unit would be very VERY useful in revitalizing the general build. i personally would love to have 5 idols to chose from (not sure if all 5 should be purchasable or if one would have to choose).