We discussed a similar idea at a team production at my university once, where the player would be in control of a species of insects that would genetically evolve during the game. It would have been cool to implement that their sensory apparatus evolved as well, and allowed for more detailed graphics and sound at later stages in the game, but looking at it from a programming and assets point of view, we decided we didn't have time for it. Still, it would have been cool, but I agree that features like those should be integrated with story and game world in a way that makes sense.