Apart from Mayweather & PacMan boxing has no superstars

[Hulk]

Bernard Hopkins is/was also a superstar.

Is.

I don't think so. Within the sport sure. But ask someone who doesn't follow boxing and the OP is absolutely right that PAC and Mayweather are the only names he/she has any chance of knowing.

superstar in my eyes

Mine too. I put is/was as I'm not sure if Bernard will continue fighting, but I suspect he will.

I've known casual fans who know who Bernard Hopkins is, very casual fans even.