This would be really interesting. If there are environmental obstacles or effects, surely there would be a way to incorporate shapechange. Turning into a rat to squeeze through a hole in a wall, turning into a bat to scout a dark cavern/room, and eavesdropping on enemy conversations all come to mind. Wouldn't mind being able to turn into a bear and bust down a door either lol.
You can actually do this with the cat form and squeeze inside Mol's lair through that hole that you normally can't get through.
So it can be done.
