i'd say so, my first report about this dates back to 2006, and its predecessors, CUBE and its derivatives, have been a great and easy-to-mod gaming kit for ages. it's maybe the most advanced open source multi platform 3d shooter engine out there. i'ts always worth to have a look at it from time to time.
however, due to the limits that puts cubeScript on you, it will be hard to make something completely different than a fps. but the source code is available (gpl), so help yourself and start messing with the source.