Mike Tyson doesnt get very much respect around this forum, so you're barking up the wrong tree in my opinion.
In my opinion and in the opinion of many boxing fans Mike Tyson is one of the greatest HW boxers of all time. His career spiraled out of control though, mainly through his own actions. Depression and mental illness is a killer even of legends.
Mike has some nice wins on his record, which is a pretty remarkable record even for a man who may or may not have lost his mind.
With Mike becoming the Undisputed Heavy Weight Champion of the world by beating Berbick, Smith and Tucker all of whom were Champions at the time has to be looked at with some respect. Mike beat an aging Larry Holmes and an undefeated Michael Spinks who was a champion(correct me if Im wrong in a different weight class).
Mike went on to regain two of the belts (WBC and WBA) against Bruno and Seldon in 1996 as well.
I think James Tillis deserves an honorable mention on Mikes win record as well, although he never quite made it to the top of the HW division. To be honest, Im not familiar enough with Thomas and his record to give you my feelings on the subject, I know Mike defended the WBA and WBC titles against him so he had to have been good enough to contend for the title.