As someone who's actually played Arms I can't say I think it would be very fun to watch even as a meme/joke thing
Marvel is the obvious pick and probably what I want the most even though I'm kind of done with being a spectator for the game just because nothing else is better and it's still Marvel at the end of the day, Windjammers and Nidhogg would be neat/fun and great as "meme games," (though they won't win) and I'd be totally okay with Skullgirls, Super Turbo, or Pokken (and I think the first two would be hype for most people, a breath of fresh air, and a good way to spotlight a less active community; I also think all three totally have a shot at winning if a small one).
Marvel is the obvious pick and probably what I want the most even though I'm kind of done with being a spectator for the game just because nothing else is better and it's still Marvel at the end of the day, Windjammers and Nidhogg would be neat/fun and great as "meme games," (though they won't win) and I'd be totally okay with Skullgirls, Super Turbo, or Pokken (and I think the first two would be hype for most people, a breath of fresh air, and a good way to spotlight a less active community; I also think all three totally have a shot at winning if a small one).