It really depends you have to look at everything as a whole I believe. There are so many factors that have to be taken into consideration, not just looking at a win loss sheet.
You used James Douglas as an example and he was beating Tucker before he decided to quit for example, it wasnt a stylistic mismatch he just stopped fighting and quit in the later rounds.
In the case of Calzahge I think there was a lot of questions about his resume up until the end of his career. Now that two of his biggest wins were soundly shut out in similar manner by (a faded Jones defeating Lacy and an unproven Ward defeating Kessler), it does tend to shine badly on Joes wins, because both wins were also one sided shut outs which tends to lead one to believe that those wins werent as monumental as originally made out to be.
Styles do make fights and are an important factor, but in the case of these two fighters they were beaten the same way by what most considered, at that point in time, lessor fighters than Joe, and I dont think it was any type of stylistic mismatch, especially when you consider the state of Jones Jr and the inexperience on the world class level of Andre Ward.
The media tends to be a bigger factor than ever in hyping fighters to a level they dont belong and people buy into it. One win and they zoom to the top of the pound for pound list.
Calzahge was an excellent fighter and probably would have done really well had he been fighting top level opposition from the get go, but a fighter like Bernard Hopkins at his advanced age having the success hes having on the world class level should be viewed more as a reflection of the state of skill level as opposed to his super human talents in his old age.
Look at Hopkins in his prime, he consistently beat every middleweight they put in front of him defense after defense and it wasnt questionable opposition. It wasnt super great but it wasnt questionable and certainly better than a good portion of Calzahges defenses which were somewhat questionable and that, factored in with the Lacy and Kessler losses is what is raising these questions, and I believe they do have some merit.