As far as Puff not being top tier - there is pretty much no argument for this.
Over the past 1-2 years Jigglypuff has placed monstrously in tournament, and not just one or two puffs, a lot of puffs (Genesis had 4 in top 13??).
The fact is that the tier list is constantly changing as the metagame shifts. Nay sayers seem to be concerned that in 6 months people will have figured out how to beat Puff (like they haven't already had 8 years, the most recent 2 years of which puff has been widely known to be a serious threat).
If that happens in 6 months, which I doubt it will, then the list can change. But there is literally no argument for Puff not being top tier AS OF RIGHT NOW. And quite frankly, based on the past 2 years, Marth and Sheik are not top tier. CFalcon should move up, as well, though CFs placing extremely well is more recent than puff and CF has yet to win a major tourney (I think, unless I missed something).