(was going to start a new thread on interaction with the gods, but I think this one is adequate)
I'd like to see gods interacting with the world, and more importantly allow for interaction with the player.
In ToEE a very memorable encounter was the one with Lareth.
When he's almost dead he tries to dissuade you, (I don't recall the details), but he then curses you and says "Lloth, help me", and 3 giant spiders are summoned.
I'd like for both NPCs and the PC to be able to worship and submit to a god, give offerings and perform tasks for him, and in return he would help you out when you asked for help. Note that there is lot of room here to balance and adapt this to the god's personality (he may as well ignore or betray you).
For example, suppose that you make a pact with a god which allows you to summon 2 of his "pets", but in return he will eat out part of your soul (ie: you lose a point on one of your attributes).
The gamers of the new school will probably say "that is stupid, I'll just reload". But for me, and I bet for the ones playing as ironman, this can be a real life saver.
Also, it would be fun to betray a god in some way or the other