Good lord, I have a lot to say for this one.
Your reasons don't seem convincing enough to me :
Geno's Mii costume is still missing. => Works better for him joining as mii costume
We have already established NUMEROUS TIMES that if Geno's outfit was coming back, it would have to come with Hero. Since Cloud in Smash 4, Square Enix Mii Outfits have only ever released alongside Square Enix characters. Its a pattern that is most likely going to continue. Its not like porting the Mii Outfit from Smash 4 over to Ultimate is some impossible task, so how in the hell does it take seven waves of Mii Outfits just to bring back this one outfit? And before you bring up how Lloyd Irving and Monster Hunter's outfits aren't back yet, I for one also think these characters have decent chances as well, so I'm not even making Geno an exception to this or anything.
Sakurai has acknowledge how popular of a request he is. => Also works for him joining as mii costume (that's what happened in smash 4)
Riddle me this, why would Sakurai add Geno's Mii Outfit again when as you said, he's already aware of the fan demand for him? Geno already got his consolation prize in Smash 4 with his Mii Outfit, what's the sense in adding yet another consolation prize when again, Sakurai is aware of the demand? Sakurai has granted the wishes of many fans for Ultimate and whether your detractor-mind wants to believe it or not, Ultimate is the Smash game all about fan-service. It just makes no sense to me for Sakurai to acknowledge and listen to the supporters of Ridley, King K. Rool and Banjo but then be completely tone deaf for the demand for Geno. Sakurai knows we want playable Geno, and even HE wants playable Geno. If Sakurai is going to listen to the support and outcry for Ridley, King K. Rool and Banjo, then chances are he's gonna listen to the support for Geno as well.
Ultimate has already added many fan requests. => 6 ou of 7 DLC characters had very little fan demand, I wouldn't bank on this argument right now (and look at what happened to Travis, whose fan demand was the strongest point)
Maybe, and bear with me on this, fan service actually IS a factor going in to the DLC? You're right, 6 out of the 7 weren't requested, but whatever point you're trying to make completely falls flat when you remember that yeah, one DLC character WAS a fan pick, and one character is all you need to say for yourself that yeah, maybe fan service is a factor for the DLC. You're right, their are other factors that do go in to the DLC as well, for example, characters that heavily advertise something like Hero and Byleth, new characters like Joker, Min Min and Steve, and legacy characters like Terry. But as I said, Banjo is that one big fan request and given Nintendo's shock over Banjo's reception at E3 2019, Nintendo would be absolutely stupid to not capitalize off of yet another fan requested character. And whether you wanna believe it or not, Banjo is a character Nintendo is doing absolutely nothing with, and probably never will. As much as I love Banjo, I will admit myself that Banjo is kind of irrelevant in the grand scheme of things. His last game appearance was over a decade ago, and his last appearance on a Nintendo system was 15 years ago. Banjo was included because of the demand whether you wanna believe it or not and if Banjo can get in as DLC, you better believe Geno can most certainly be a contender for DLC as well.
It seems almost guaranteed that at least 1 Square Enix character will be in this pass. => Also works better for him joining as mii costume since there are a lot of other square enix candidates.
If you actually seen the thread on a daily basis, you would know that not a single person in this thread has EVER denied the fact that other Square characters have shots as well. For example, I think if not Geno, Lara Croft has a somewhat decent chance as well. But this is obviously the Geno thread, a thread where Geno supporters talk about their most wanted character joining the battle. Obviously everyone here is gonna have high hopes for their most wanted character to join the battle. Maybe its because we are actually optimistic about our character? Shocking, I know.
It's weird that you can be confident that Geno will be playable when all your reasons points to him being a mii costume.
Yeah, because god forbid we actually have high hopes for a character we all really wanna see join the battle. How dare we!
End of rant.