One of the important forces in game selection is "We want it to be just as much fun as the old days, when we were new to TTRPGs." Parts of that are impossible: no experience can be as much fun as the first time you got it to work right, and it was really cool. To achieve that feeling again, you need to be doing something significantly different, so that your experience is new and cool again.
I've found I can get "this is new and cool" from campaigns with different settings using a familiar game system. I've done this with BRP and GURPS, but not with Hero System, which I've found is always trying to do superheroes. This may be the result of the GMs I've played it with.