There are so many games where the designer had one good idea but (rightly or wrongly) felt that they had to publish a complete system without copying any existing system. Which, to me, is silly.
The great thing about the retroclones & such is that they can re-use all the time tested stuff & just add their few good ideas to it.
That said, I generally don’t actually play those games. I play B/X D&D and import things I like from other editions, clones, etc.
Although, after saying all that, I’m running DCC right now. I suppose because it does enough differently that it feels like more than just a clone. Well, actually I suppose I’m running it because I find their adventures easy to run with low prep & low prep includes just running the system it is written for.