One thing to consider, too, is that they might count votes from Golden Sun in general towards Isaac, since getting a secondary character is extremely unlikely. It'd still be better to vote specifically for Isaac, of course, but regardless, any votes for Golden Sun show that the franchise is still popular, and pretty much everywhere I go, Isaac/GS is the most requested Nintendo character/franchise that's not playable in Smash already.
See, this is a GREAT point.
Here's something everyone voting for Shovel Knight is FORGETTING:
Shovel Knight hasn't been released in Japan.
Shovel Knight is being widely talked about in western circles. But in Japan, Shovel Knight will go flat, because it was -not- released in Japan, and probably will not be any time soon. That's a significant portion of its votes down the drain. Isaac will definitely get at least a few requests over there, and K. Rool is among the most popular newcomers in both regions (from Nintendo he'll be the biggest newcomer pretty much guaranteed, its not even close).
As for Dixie, no, she probably won't be higher than Isaac, because most of the DK fanbase is voting for K. Rool. Overall she probably has more popularity than Isaac, but until we get K. Rool, her votes will be drowned out by K. Rool's votes.
I'd love this, but I'm just content getting Isaac in the first place. ^^