I'm considering having priest's and other divine spell caster's (shamans, druids, and so on) primary shtick being that they make a contract with a god or powerful spirit and then gain the ability to summon either the god itself (for lesser gods or powerful spirits) or servants of the god for more major gods. Aside from letting the god/spirit into this world, they have no power of their own. The idea behind this is that unsummoned gods and spirits can't affect the physical world much, at most they can manipulate probabilites when it comes to their area of influence (resulting in their priests seemingly having extremely good luck when it comes to the god's area of influence) but they can't do anything impossible. So they need a priest to summon them to let them muck around with the physical world. The priest gets the protection of the spirit/god, the gods get to muck around in the physical world and advance their cause. Plus, seeing a god appear to lay the smack down on the priest's enemies does remarkable things when it comes to getting people to flock to their religion. ^^ So..... what do you guys think about this? Good idea, bad idea, corny idea? Any obvious plot holes you can spot? etc and so on. Any input would be apreciated.