Since you can re-summon your dolls (yea i know they have a time penalty, but thats nothing major), they handy to "feed" to monsters, while you have fun killing them.
They also make BRILLIANT trap finders (the hard way)
Since summoning dolls cant venture far from where you summoned them, its useless to try and make them survive for long... they are only a distraction to monsters.
I had 3 summoning dolls that i alternated as monster-food, by the time the last one is dead, the first on is ready to be summoned again.
Keeping 2 char's alive is a different mindset than just 1. You learn the value of the pause button much faster with 2 char.
Setting the ranged char (mage / archer) to non-leader and agressive mode, while your melee char (warrior / mage) is the leader gives a very big advantage. Your ranged char will automatically attack any monsters in range, killing / injuring them before they reach you.