Though those results are impressive, they still don't lead me to believe that a Diddy will come close to winning Genesis alone.
So long as M2K is around then technically the only viable character to win is MK. This also means that the only characters capable of winning in Melee at current are Marth and Jigglypuff. You should notice that in Road to veridian city, which is basically a regional/large local, that NL got 5th place. What place did NL get at COT4? 5th. So, different tournament, not "national" or "regional" but NL gets the exact same placement, which should give you an indication of the type of skill level at the tournament ADHD won (ie NL at COT 4 gets 5th with the best from the MW, SE, TX, MD/VA, CAN in attendance, then NL gets 5th at a tournament with just the strong NY/NJ players for the most part).
At the top of the chain it is largely about the players skill level. Characters obviously factor into it some (you can only go so far with Jiggly in Brawl), but there is only so much that can be done against the likes of M2K. Essentially, characters that don't have any completely poor match ups, like Diddy or MK or Snake, can win tournaments because it comes down to who the better player is. If you are better than M2K skillwise then you can win with Diddy/Snake/a few other characters. It is that simple. Also, you should note, that I believe Diddy is the only character M2K has lost full sets to in tournament (where MK was not banned) since last summer.
But what will you do on a stage like Rainbow Cruise? Say you're in the grand finals, and your opponent plays Falco. My assumption would be that you would have banned Japes, is that right? So then your opponent CPs you hardcore, and takes you to Rainbow Cruise. He/she knows that you would be staying diddy, (Another disadvantage. If people know you only have one character, they are going to capitalize on that to the highest degree.) And then they would choose MK or even Kirby, or GaW for Rainbow. Having said that, not only are you at a matchup disadvantage with those characters, but you're also at a severe level disadvantage.
Diddy is not helpless on other stages, this is a common misconception. I banned RC against Snakeee at COT4 because I knew that was his best stage and he took me to Norfair because he assumed like most do that Diddy is bad there. It didn't work, even though on paper you would say ZSS vs Diddy on Norfair is lopsided, possibly heavy, in ZSS's favor, Diddy has all the tools to deal with anything on every stage. I played this MW player named Infern (who came very close to knocking Ally out of winners at a tournament 2 weekends ago) 3 weekends ago and banned Pirate Ship against his Ike, he took me to Norfair instead and I 3 stock him only taking 61% (after he barely, barely lost the first game against, I was over 100%). That said, as Diddy, I expect to LOSE my CP. I don't even care about my CP half the time and usually just use it to mess with an opponent/figure the opponent out. All the weight of a set for a Diddy player is on the first game. I will win that first game against anyone I'm better than, and I will win that third game against anyone I'm better than, and in the end its about who wins the set and not who wins some random CP stage (which Diddy isn't all that bad even).
Examples from the first 2009 MWC event:
-Kel I decisively (1 stock low or mid %) beat game 1 and 3 and barely lost game 2 on his CP of Frigate while using MK (admittedly I played bad that game, overall I'm 3-2 against Kel's MK on Frigate)
-Needle of Juntah I 2 stocked games 1 and 3 (almost 3 stocked him game 3) but game 2 I lost barely by a lucky 9 from his GW.
-YBM I beat decisively 1st game and by 2 stocks the 3rd game. Game 2 I barely lost on Brinstar.
Heck, in pools, three different people tried to CP Luigi's Mansion against me, using Ice Climbers, MK, and Lucario. All three lost. I even 3 stocked the MK player.
That is basically my typical tournament. Game 3's all over the place, but in the end Diddy prevails because he can WIN the CP's if he really needs to, but he mainly just has to win game 1 and 3 (like every character, except Diddy is strongest on neutrals).
Essentially though, to make this simple:
-You overrate Diddy's weaknesses on stages
-You overrate Diddy's weaknesses against characters (his worst matchup is probably Falco and its just a slight advantage for Falco)
-You assume people always try to CP to their biggest advantage. This is false, rarely does anyone CP to give themselves the biggest possible stage/character advantage. The potential exists, it is just extremely rare.
-You also assume people can play multiple characters. Most, if not all, can't. Typically people have one really good character and then a secondary that is about 3/4ths of what the main character is, so still good but if you were going even against Diddy with one character and lost (chances being that character was roughly even with Diddy, like all characters) and then you switch to another character that character will probably get wrecked. For whatever reason people have attachment issues with characters. I could switch to MK or Falco or Toon Link or whatever, but I'm not going to, I like Diddy, he is my homeboy. Do some people have multiple characters? Yea, duh, Azen. But I would put money on ADHD against any character of Azens (except maybe Lucario, stupid Lucario is up with Falco against Diddy, plus its Azen so you know he is going to do everything right and nothing wrong ever ).