Well, I will admit that Daisy has been in a few games recently. But like I said earlier, they are games where the purpose of having different characters were more a change of scenery than developing the characters themselves. I have yet to see a game where Daisy concretely differentiates herself from being Peach with a different look. She's more tomboyish? Why? Because it says so on her SSBM trophy? Have her beat the living daylights out of Bowser when he tries to kidnap her, THEN you can tell me she's more tomboyish than Peach.
Been around longer than Wario? Sure, but let's look at quality, not quantity. After all, Goombas have been around about twenty years now, and the biggest change they ever got were wings. Wario went from being an uninteresting, evil Mario, to having his own games, his own distinct moveset, personality, and even genre in the form of WarioWare. The only ties he's had to Mario since Mario Land 2 are his similar costume and inclusion in the Mario sports games.
Daisy has yet to play a significant supporting role in any game. Supporting roles? Yes, you've cited many examples. SIGNIFICANT supporting roles? No, in every game she's been in, her role could have been filled by a common household plant, or at the very least Peach.
Don't get me wrong, I'd say Daisy's got potential to be a great character, and I'd love to see Nintendo develop the whole Luigi/Daisy thing, but the truth is she isn't there yet. She needs some development in the Mario universe before you can justify bringing her into the Super Smash Bros. universe, because Smash is supposed to take only the best from each game, not every little cliche overused character, otherwise it would be bogged down by all the useless uninteresting, unnecessary, and pointless crap from every Nintendo game they choose to pull from.
Here is the plain fact of the matter; If it were not for Super Mario Bros 2, there would have been no reason for the inclusion of Peach. Actually, as things stood, I was pretty pissed that they put her in SSBM until I got good at controlling her, because Mario 2 is basically the only game that separates her from being a part of the scenery. And who knows? Perhaps sometime Daisy will get the same shot. Maybe a Super Princess Sisters or something like that. Ew. No, scratch that idea. Point being, as soon as we see Daisy as being more than background scenery, accomplishing something uniquely hers, having some bearing on the plots of the games she is in, heck doing anything more than existing in slightly varied way from Peach, then she might warrent consideration over the hundreds of other background characters. Super Smash 4? Maybe. Super Smash Bros. Brawl? Sorry, for those of you who like her, but no.
Btw, as far as the comments about Pichu, the answer as best I can tell you is that Pichu was included because there were five Mario characters and only three pokemon characters. Pokemon seem to draw in a younger crowd, so Nintendo seems to like to force them down our throats at every instance (nothing against the mainstream Poke games like Red or Gold, as they are good games, but things like Pokemon Pinball?? Come on). As you have likely guessed by my cynical nature, I agree most wholeheartedly that Pichu should not have been included, as he is nothing more than a baby Pikachu. But a baby Pikachu which was very popular within the Pokemon fanbase, none the less...
The short answer? There's no justice in the world.
In any case, if they throw in Daisy I won't boycott the game, but I really don't want her in because then there will be nothing to stem the tide of inevitably minor and insignificant characters which each and every fanboy/fangirl will want included simply because it is his or her favorite. End rant 2.0
Andy