Um, the realistic one takes in my knowledge of tourney results, which is why mario comes up irrelevant (I had him as top of C in that list). That's also why DK is higher, because I haven't seen luigi's doing to well, and when it comes down to it, I don't see any matchups that luigi has easier than DK.
While luigi is amazing at not getting combed, and has decent ground game, he has to work harder than DK, and suffers from a very mediocre recovery, even with good DI (it's worse than mario's better than doc's, but not that good). I don't have much experience with seeing those two, so I may be a bit biased. (wait, I must never admit that--must just say I'm right and call you a n00b =P)
Also, I don't get why bowser would be a top 3 char theory wise. All he has going for him is upB OOS, which coupled with theoretical perfect fortresshogging is still not great. Even after getting hit by the up, many characters and get him back before the fortress finishes. chars like fox falco and shiek have frame advantages over his shield (especially assuming perfect play), and if he uses the fortress to go through attacks, he can just get grabbed or baited.
Though theorywise, I guess puff would be top 3, as she has a 1 frame ko move...oops.