You don't have to take my word for it but if I were you I'd work my ass off to prove them wrong. I prefer to have my hands at about shoulder/chest level unless I'm throwing a punch and bringing the other hand up when needed. You know that even James Toney when he was working with the moves like his shoulder roll that we take for granted he got knocked on his butt in the beginning but he kept working on it and he improved it to grace that we've seen him bring into his fights.

All the techniques are out there, a good place to look is at the fights by those great fighters that you've mentioned and finding other fighters that have the moves that you're looking for. A lot of good fighters improved themselves by watching fights, including the great ones such as the Sugars, Ali's, etc.

That's something you should explore. So when someone says your left is low, you don't just tell them, you show them why. "Throw me a right hand and I'll show you what this is all about!"