ToME WikiRavenRed: Just a slightly longer idea.
Summoning, at the moment, it explicitly magical. Monsters "suddenly appear nearby", and in pretty much all cases right next to the player. This is fine if it's a magical effect for magical creatures. But for more mundane beasties and summoners it's a bit of a stretch that the creatures wink into existence upon a few muttered words of power.
My idea to rework this is for monsters that have been summoned to appear from either the nearest level exit/entrance or from a random exit somewhere on the level. This makes summoners somewhat less IMMEDIATELY deadly, as the called monsters would have to move to where the actio nis. This method ("Calling" monsters)could co-exist with the currently more magical way in which monsters are "Summoned", depending on the monster or caster type. Two ways in which this could be done:
1) The monster(s) are created all at once centered upon the exit square, similar to the current system.
2) The monsters appear one each turn on the exit square. This involves the monsters being "queued" whilst their fellows exit onto the level. It could take some time for a large horde to appear. This is a slightly more complex and messy way to work this, however.
2c worth and counting...
LordEstraven: This is a pretty cool idea. However, it doesn't make sense in all cases; summoned spirits, for instance, should appear near the player. I'd say a flag is in order, to tell the engine if a monster is to be summoned where the spell is cast or called from another level.