Actually, most people are probably unaware of the raw numbers and/or don't trust them, so it may not play into their perception of anyone. I know I don't pay that much attention to them, because I'm not sure I trust them all that much. Given that Ricki and Derek both had fans coming into the competition and that Karina isn't a huge favorite among long time viewers and that J.R. wasn't all that well known, I don't think it's unreasonable for people to have assumed--or to continue to assume--that he may not be a shoe in to win. I think he's likely made more fans for himself because of the way he's handled himself on the show, but that doesn't necessarily mean all that much either. Gilles went from someone not that many people knew to a huge fan favorite and he was paired with Cheryl, a multiple winner, and they still lost to Mark and Shannon.
A lot of it always comes down to how they handle the finale, and we never seem to know what the rules will be for that, because they keep changing them.
I think fans of R/D and J.R./K both have reasons to be concerned about the competition.