Probably one reason why she gets a lot of hate from the Smash fanbase - her getting in Smash would hurt the chances for a Xenoblade character, as well as another Bandai Namco character.
Allow me to clarify on something that's very important regarding the overall reception behind KOS-MOS (outside of the support base): From what I've seen, a fair amount of Xeno fans are pretty open about her possible inclusion over anyone else they're more familiar with, and it has to do with acknowledgement of seniority. There's also the exposure they had in Xenoblade 2 with her infamously difficult-to-obtain cameo appearance, and the fairly recent rise in attention thanks to all of the bull**** leaks.
This includes that one person who joined this forum and commented on this thread just to boast and gloat about the drunken cat leak being fake. Whatever pot they tried stirring backfired pretty badly, because all that happened within that time frame of the last couple of months in 2019 is boost her popularity further with the unassuming Smash crowd. Hell, we even got some naysayers as supporters, so that's an improvement in my book. If another Xenoblade character made it in somehow instead, I'd still be really happy, because I've become a fan of the Xeno franchise in general. Kosy just happens to be my #1.
Not just one reason. It's THE reason why there is a ton of hate towards KOS-MOS and her supporters. It all has to do with her general unfamiliarity among the smash community/speculation scene. it's very similar to the Catalina incident that happened near Ultimate's DLC. the community threw a freaking party commemorating her exclusion and finding out the fighting game she was meant to appear in turned out to be Granblue Fantasy Versus.
Yeah, that incident was quite sad. Personally, I'd like to see Artoria make it in with playable representation from the Fate Franchise and Type-Moon as a whole before Gran, Djeeta, or even Katalina. I'd be absolutely fine with a Granblue Fantasy rep though. I really dig their character designs, the general layout of their world, the music, and even the artwork itself. Imagine the hilarity if we got either-or after all.
Her in smash also means she was the selected Namco rep which wouldn't sit well with fans who wanted a Tekken or Tales of rep in the pass. the same also applies to her chances vs. other xeno characters but something tells me the xenoblade community would be a little more understanding/happy if KOS-MOS was chosen seeing as they are from the same franchise.
Sadly, there is definitely a lot of in-fighting within the Bandai Namco support base. If we look over at Capcom's side, fans are generally excited about the prospect of most candidates possibly making it into the roster as playable fighters. Unfortunately, it's almost do-or-die over here, and given the Chrono-Trigger–like nostalgia that Tales of Symphonia receives, along with its competitor Tekken and its significance to the fighting game genre, they both often look at Xenosaga as a failure franchise and "waifu pandering", which instigates the bravado they have over a character they feel isn't or shouldn't be rooted for. Meanwhile, newer fans of Takahashi's games, namely the Xenoblade community, are far more open about the possibility. We've already established our points so going back on it is needless repitition.
her recent rise in popularity due to those fake leaks and mysterious ultimate mod takedown have at least proven to work in her favor in terms of awareness/potential boosts in popularity for smash DLC inclusion or general support for the character. who knows? it might be enough to get her in smash 6 if she doesn't appear in the fighters pass vol. 2 though that last bit may be a bit too optimistic
That mod takedown was just a coordinated troll move that coincided with the Game Awards speculation. I'm 90% sure that person (AKA our "drunken cat leaker", if they're still here) was responsible in orchestrating (or at least partaking in) a reported takedown. The fact that Nintendo never even bothered removing the other videos of her just confirms the suspicions I had day 1, even when the modder I commissioned notified me in private. That's just the sad reality of it, so we're left in the dark like everyone else.