I liked Nemesis, but it has it's flaws, maybe we could compromise:
Shinzon still could have been a clone or something, but they really did NOT need to create the Remans. The plot would have gotten on just fine without them. The new Preator could have been a known Romulan. Like Tomalak or Sela; not some new character created just for the film.
Not that it would have been a successful film finanically given it's competition, but it would have been more enjoyable overall at least to me.
With your idea, I don't see the need for including a clone at all. If you want a Romulan praetor (who I am assuming would be the main villain) what is the point of having a clone? Unless you want to use the clone to replace Picard?
I did like some of the rumored ideas I heard about Picard already being replaced by a clone. I think that could've been an interesting way to go. But really, I don't think NEM needed a clone villain or the Remans.
I also don't buy that competition alone killed the film. It didn't just under perform, it bombed domestically. If the film had been good, to Trek fans alone, then it could've had a decent enough run, and you might could say that stiff competition kept it from earning more. But since it bombed, competition alone isn't the reason it failed. And I'm saying this as a person that came to appreciate NEM upon a second viewing. It's not completely bad, there are potentially good ideas there that just aren't realized.