Thing is that would be quite good just making an engine and the A.I brains and media plus player controls so you can possess the A.I plus get into and out of Ground and Air vehicles, including horses, chariots, Dragons, other creatures of Mythology e.t.c. that they player can put together and let his creatures use, eat , kill e.t.c
and just let them make what they want, so in a way they are making a game themseleves although a lot less harder than what the programmer has to do.
Yes I argee RPgamer came out with avery good idea there