If MapleStory could have a crossover with a TV Show...

SAO could come with;

1) (NX) equips
2) bosses
3) theme dungeons
4) porting over and remixing some of the iconic soundtracks for said theme dungeons/bosses
5) hairstyles/faces
6) MapleVille additions

If the development team really wanted to do a good job, crossover content from SAO could potentially be amazing. Of course, I am aware that some of the things I listed are expecting too optimistic. But nevertheless, there is certainly enough content to make it worthwhile should they decide to put in the effort.

Like I said before, I don't know anything about Adventure Time. I can't imagine, however, a simplistic comedy cartoon providing nearly enough hype. If anything, they'd be better off crossover-ing from The Simpsons or something.

That is far too ambitious.

Look at past crossover events, what have they given us? A few nx items, a few equips and some NPCs. Thats it. You really shouldn't expect things like dungeons and bosses for a simple crossover event.

And in terms of things which could be made into items, adventure time has a lot more cute and iconic characters. SAO has like 2 popular characters, no iconic weapons or outfits or pets. And so the creative options of a SAO event is very limited.

I think you're being far too harsh on it. I think the only way it is generic is that there is nothing that really sticks out about it, and when I say that I mean like themes or outfits or a mascot or something.

I'm not really being too harsh, it's my honest opinion. I find the show generic because it's got shoe-horned and unbelieveable romance, and a main character who defies the very rules of the games he's in because he always has some unfair advantage that makes him instantly better than everyone else.
There are literally only 2 memorable characters from the show: a typical overpowered male protagonist and a tsundere love interest. There are no iconic outfits, settings or anything.

I think it's a generic shonen series that tries to pretend it's "deep" and it boggles my mind why it's so popular. I can understand something like Naruto which has had a following for a long time, but this series gets more hype than it deserves.