The key here to me is that in-order for me to really enjoy a RTwP, you must have well written AI, both in quality and quantity. I would start by suggesting that they look at Icewind Dale II for examples of what I consider well written AI, and then expand it to include utilizing the environment (this is the hard part).
However, on the plus side, once you have written out all the various AI (not just for PC classes, but for summons (such as Mage Hand)), you could probably just assign NPCs and Enemies those AI instead of scripting individual AI tailored to each individual.
