Noel Vermillion
A pretty prominent and popular character in BlazBlue, what makes her special is her use of guns and weaponry which will be a good stark contrast to others in this submission.
What will she represent?
New Company. Recently Smash has introduce us with 2 company being represented, one being Microsoft, a direct competitor to Nintendo and made everyone mind boggled with the inclusion of Banjo and Steve that pave the way for more business collaboration, and second being SNK, a company that undergo major ups and down from being on equal foot to Street Fighter in terms of popularity that resulted in a crossover game and going bankrupt at many points in time to we are now today.
Arcsys, just like KT is a major ommission for many people, one reason being that they have a big legacy on their hand mostly because their old game are tied heavily with Nintendo (Double Dragon and River City specifically) and they are a big figure in the world of fighting game being the sole company that made a few bangers like P4A, DBFighterz and Granblue Versus and is very faithful to its source material and with the release of Strive giving Arcsys more attention and interest, another information is that Arcsys has some representation in Smash in the form of the River City spirit event so them hoping over as a fighter wouldn't be that strange
Anime Fighters. It's a major subgenre in the world of fighting game, it's basically taking the traditional 2D fighter and amp the gameplay to 11 with more flashy attacks, increased speed, an F ton of unique gimmick for almost every character in the game and of course the anime artstyle and BlazBlue is basically the poster child of its genre. Of course in Smash we're missing out on that, we already have 3 traditional 2D fighter in the form of Ryu, Ken and Terry and not too long after Kazuya came in representating 3D fighters, and while it's still count as a 2D fighting game the unique implementation is enough to make it distinct.
New playstyle. So far our reps for fighting game has just been all punches, fireball and swords, Noel is a little different as she dual wield a gun and would make for a great moveset basically fleshing out Joker's neutral special and made it it's own character. Here's a video showcasing her move:
Why BlazBlue over Guilty Gear?
While my cases could be applied to both BlazBlue has some going for it that eclipses Guilty Gear, one being that it is the first Arcsys series to hold a crossover between Persona 4 Arena, Under Night In-birth and Rooster Teeth's web series RWBY followed by Senran Kagura, Arcana Heart and Akatsuki Blitkampf so if wouldn't be out of ordinary to have them in Smash.
BlazBlue also has additional side media in the form of visual novel, XBlaze, manga, Remix and Variable Heart and light novel, Bloodedge Experience all of which expanded the world of BlazBlue, it also have an anime adaptation and a few other collaboration, and I haven't even mentioned the radio show hosted on Nico Nico that has been a thing since the early 2010 usually to promote a game release.
Note; I'm writing this on mobile, so sorry for the lackluster formatting.