Or Ridley!
I don't think he'll make it in, Mushroom Kingdom reps are already way overdone.
'
He's too big.'
Ridley's size is hardly an argument. Smash is meant to bring fan-favorite Nintendo (mostly) characters into playable fighting form. As long as a moveset can be created for them then they are Smash-capable. Ridley size would not interfere with this. Bowser is a good example, as he has been much larger than Ridley ever has been in some games, but in other games (even Smash) he has been downsized to fit whatever role he is given. Ridley's role has always been as a boss. (an important one, at that) It's only natural for him to be large and imposing for this role. Ridley's role in Smash? To fight ofcourse! So he would be easily downsized so he could do so with the rest of the Nintendo all-stars.
'
He would look awkward.'
Ridley is large and lanky, yes. But, that is just how Ridley is. It's part of his character. He could still be made to fight in the world of Smash quite easily. Donkey Kong has a huge head and long, large arms, but small legs in comparison. Kirby and Jigglypuff have tiny, stubby arms and huge feet tacked on their round bodies. Yet, all of these examples have proven Smash-worthy, have they not? He may look a little different from your average human-shaped fighter, but give him a chance.
'
His design would be too hard to implement.'
Long head with huge powerful jaws. Great, mighty wings. Long, claw-tipped arms. Long, flexible pointed-tip tail. All part of the Ridley design. How could they implement all these great, fighting features you say? In Melee, that might have been very difficult. This is Brawl, however, and the recently confirmed Charizard throws this argument away. Charizard also follows the draconic design, so if they could make him work, then so too could they make Ridley.
'
He would be an Assist Trophy.'
Ridley? An Assist Trophy? Let's look into what has been confirmed Assist Trophy material.
Hammer Bro. - A generic enemy of the Mario franchise.
Nintendog - Something to represent a very successful franchise that otherwise, could not have been represented in Smash. (Think of what critics would say about Smash if you were able to kick around a cute little puppy!)
Samurai Goroh - A rival of Captain Falcon. He was one of the first four F-Zero characters. Seems important enough to be playable, doesn't he? Not really... F-Zero hasn't really come along as a franchise as much as Metroid has recently.
Main villains, like Black Shadow and Deathborn would be more likely if F-Zero were to get another representative. That is what Ridley is, a main villain.
Dr. Wright - Like the Nintendog, he is here to represent a series that was popular, but otherwise did not have enough going for him to make him playable.
Knuckle Joe - An enemy and helper character of the Kirby series. He's not important to the series, but is highly popular. Kirby is likely to be better represented this time around, with Meta-Knight and King Dedede joing him for Brawl. Knuckle Joe was likely just included as an Assist Trophy for his popularity.
Devil - A character from an old, popular game. He was included for the nostalgic effect, it would seem.
Andross (Old) - a floating head he may be very important and a last boss but in the end all he is is a floating head... nuff said.
Now, Ridley is not a generic enemy like a Hammer Bro or Knuckle Joe. He is an important part of the Metroid series; He gave Samus her motives for becoming who she is, basically. He's a highly important villain in a very popular series in need of representation, unlike Goroh. Unlike the Nintendog and Dr. Wright, he is capable of fighting, and his respective game(s) is not old. The Devil is there to represent an old popular game series, something Metroid is not.
So, from what can be gathered, Ridley is not Assist Trophy material.
'
He would be a boss.'
Ofcourse he should be. That is what he always has been. Does this mean he should be unplayable? No way! Bowser and Ganondorf have also been bosses, but they are playable in Melee. (Ridley is often considered the 'Bowser and Ganondorf' for Metroid) The recently confirmed boss, Petey Piranha, is not important to the Mario series. He's popular yes, but not important. Meta-Ridley, the huge cybernetic Dragon of Metroid Prime would make a great boss, in fact. He could stay his huge size. And attack in the same method. Dropping bombs for players to catch and throw back at him. Once grounded, he would use his dash attack to try and knock away players. That is when you dodge, and attack him during Meta-Ridley's lag. If you don't cause enough damage, look out for his plasma beam! It could be quite intense! 'Classic' Ridley however, could also be an earlier 'boss' that you must fight and defeat. He would be like a normal playable character, though. (Although probably made heavier to make him more difficult) Only later will he return as the monstrous Meta-Ridley boss. You may notice 'Boss Fight' in the title of Ridley's theme. This is only the name of the song used in the games, the 'Boss Fight' there to show Ridley's boss status in his games.
'
He isn't popular, and non-important to the franchise.'
Nothing is further from the truth! Ridley is shown to have a long history with Samus herself. Him being the one who led the space pirates on the invasion of her home, destroying it, and her parents, in the process. He has always appeared as a boss in most of the Metroid games. (All but two, Metroid II and Metroid Prime: Echoes) He is also very popular. In Sakura's poll, from what he allowed us to see, Ridley was mentioned four times; The same amount as Diddy Kong and Ike, both of which are confirmed playable. These polls were japan-only, a place where Metroid is not very popular, yet Ridley is still very well-known there, and he is wanted.
Are you really stupid or just plain ignorant?
*insert other random Metal Gear Solid 3 quote here* 
Get a real reason next time, not some stupid saying=lame! 
