As much as I dislike Antonio Tarver for knocking out Roy Jones, he is not a one-win wonder. Tarver beat Glen Johnson, Eric Harding, Clinton Woods, Reggie Johnson, Montell Griffin, Danny Green, and I thought he beat Lateef Kayode. Those are a bunch of decent-good wins, that is on top of starting late in boxing.
I think Maidana is a pretty good shout actually. He's a brave fighter, with heavy hands, but awfully limited. Failing to get Khan out of there in the 10th round is pretty damning too, he lost all control and just wailed away with wild left and right hooks, instead of whacking the body and using the uppercut.
Tarver is a one hit wonder, in the sense he was touted as the best light heavy by many idiots over one win. The fighters you named some are pretty good, but none really elite. Tarver had the audacity to start calling himself the "legend killer," which is total garbage. He was completely owned by Chad Dawson and Hopkins, far from a legend killer, RJJ is the only elite name on his resume, and RJJ was FAR declined. Tarver is a gatekeeper at best, and would be a journeyman in any decent era.
garciavs khan? If you drop a man who arguably has the best chin in the business you've got to have some quality