The feature that I would really like to have seen would be one that automatically tracks and randomizes the monsters in play. I think it should be perfectly usable if done through a touch screen, with just a few presses to dismiss and spawn monsters.

I'm really concerned about how my poor little eldritch monstrosities will fare over time with all the wear from mixing them about in the bag. Other solutions, like a chart to roll dice against, don't seem very elegant and/or adjust the probabilities. A program to sort this for you would be awesome. You could just have the monsters neatly stacked up beside the board - of course needing yet another acre of table space though...