Freestyle Wrestling (International/Olympics) = Explosive take downs and throws, very little ground time
Folk Style Wrestling (USA only) = Some take downs and throws, tons of ground time
Romero is a born and raised Free Style wrestler, and is explosive by nature. He could take down anyone to ever compete in the UFC, but it wouldn't really help him in an MMA match since he was never a "blanket" kind of wrestler like most Folk Style (USA) wrestlers are.
Romero could, and IMO should, use his elite TDs more, but he'll never be a dominant top game kind of guy.
It's not who he is, and his wrestling isn't geared towards it.