Mayweather doesn't get the credit he deserves because the style he fights and the talent he has adds up to a lot of fights that aren't competitive because his opponent simply can't land anything.
The hardcore boxing fans and writers will always appreicate the technical skills of a fighter like this, but the casual boxing fans and mainstream media will never appreciate it, because his style is about defense and speed instead of brawling, blood and KOs.

Whitaker was constantly labeled as boring and was never able to attract big crowds or PPV numbers. I'm sure Willie Pep was labeled boring at times as well. I consider Whitaker and Pep to be the two closest comparisons to Mayweather.