I could still see some of the lower tiers moving up simply because their metagame is not yet as developed as the higher tiers have. Taj for example has showed us his amazing Mewtwo, Chu has been showcasing his Pichu and Bum even came second on Gauntlet using DK only. It's been quite unheard of that low tier wins any money on big tournaments and there were many big names there, like PC, KDJ, Zang, Wes... plus lots of other known smashers. So imo, Bum's DK is what stands out the most of these three developments. There hasn't been any competition of who has the best DK (Captain Jack) until now that Bum has showed up and if these two players would succesfully play DK on big tournaments and do great (or perhaps just Bum doing great on every tourney he enters, dunno how much CJ uses DK on tourneys), perhaps it would inspire more people on playing DK on a higher level and a rise on a tier list would then be more than justified, even though I don't see that happening with the big gap on the updates. You don't look at the whole metagame itself as a reason to not have him rise on the list when certain character's metagame is still undeveloped. Just how many have played DK on big tourneys and won money? >_>
And Eci4, Bum has some 2 months old vids on tube, search for ssbm+Bum and you'll find them. The first one me thinks has 74% damage combo on fox, that was amazing to watch. I could also easily see him improving a lot during those 2 months. ^^