Hm...*rubs eyes* Grammer is a good thing. Really.

Everything has been done before and will be done again. Nothing it new.

Saying that, you can improve upon an old formula. Look at FFXII. They changed everything on how battles work out, how stats and moves are learned, but they still kept it Final Fantasy. Look at Bioshock. Look at Spore. Look at the Half-Life series. Look at Supreme Commander. Look at DEFCON. All of the games said have taken something normal, something that has been done over, and recreated it to become something new. Something new, with some familiarity inside it.