Guess i'll throw in my 2 cents.
No.
..Oh right, I have to give reasoning for it.
For starters, being the villain or not, he's not popular, he's just that big head at the end of the star fox games that you have to kill, unlike many other villains in Melee, Andross creates NO hype to the players.
For example, you're playing Ocarina of Time for the first time, right? You get to the part right outside of Hyrule castle as a child when Zelda runs away with Impa, and Ganondorf appears.. GASP, it's Ganondorf!! When you see him, he creates much more hype to the players, and there's a bigger story behind him. Now Andross: *Beat level 4* Okay, we did it, we must stop Andross! *Beginning of the first level* Look at what Andross has done! We must stop him! And when you get to him, it's just a big head with 2 big hands, nothing special about him, more like you just wanna kill him so you can beat the game already.
This applies to every villain in Melee/Brawl. There's something about a character that creates a hype in a person. Since we're talking about villains, who remains..? Mewtwo and Bowser?
Mewtwo has his fan base from the movie "Pokemon: The first movie", where he was an immensely strong figure with incredible psychic powers, and was the main antagonist in the movie. Aside from that, he was also the game's strongest (By popular opinion) pokemon. And Bowser, besides being in many Mario games, both a hero and a villain, he has an attitude to him! Mostly shown in Super Mario Sunshine and Super Mario RPG, where he's a spunky dragon/turtle with an enraged attitude. What does Andross have? Nothing! Very small fanbase, creates absolutely no hype, it's just a big face. Sure, you say he'll have a body in Brawl, but nonetheless he's just so.. unimportant. He could easily be compared to Wham Bam Rock from Kirby Super Star, a big head with 2 hands, and as we know that's just a generic boss.
Now Wolf on the other hand. He's got a much bigger fanbase, more attitude, creates a hype around him, and he was also in the Melee intro video fighting Fox. If Andross was so great, that Nintendo would've seen him as important to the masses, they would have had a video of fox shooting at Andross wouldn't they? Not fighting his main rival. I know Wolf and Fox seem so similar, but this is Nintendo we're talking about, they could give the sandbag a moveset and none of us would even expect it, so of course they could make Wolf different from Fox and Falco.
Now, on to my next point. Him with a body.. No. It's a fat monkey head, repeated again, and again, and he always has been. Give him a body, draw me one, and tell me with his figure and shape, he'll appear to be something that even looks half decent, especially on a game like Smash Bros. Sure, Nintendo can do anything, especially giving Ridley a size worthy of Brawl, but that's because he has been Samus' size before, Andross on the other hand has always been a giant head, be it that he was a proffesor or whatever you said he was. I won't delve on this point long enough, no point in it.
Sooo, as it stands, no Andross for Brawl, Wolf for Brawl/Fox's main rival!