Sadly, some fans won't. Hence all the fatass jokes about Samoa Joe. Never mind that he's a perfectly decent athlete who can work hour-long matches, he doesn't have shredded muscles, therefore he's a couch potato to some people. Years and years of the WWE and everyone who copied them constantly giving us roided-up monsters as "real athletes" and "looking great" have conditioned plenty of people into that exact mindset.
I think that's all in the presentation. Again, like you mentioned, it takes conditioning of the audience. Pro Wrestling has that luxury though. Even Edge comes off well and he's got a lean, athletic body. I do think, had Joe been booked better, he would be taken seriously and accepted. When he was in ROH and first coming into TNA I don't remember nearly as much talk about his lack of muscles as there is now that he's a knife wielding whiner.
Well there's also the fact that he absolutely sucks now and has gained at least 50 pounds.