https://www.sourcegaming.info/2019/09/11/sakurai-talks-more-about-smash-ultimate-dlc-development/
New Sakurai column, including how he and Nintendo decide on characters, how many breaks he needs, the ease of working on DLC versus an entire base game, Sakurai's desire to work on a GROWING Smash game rather than what prior titles were, and something that is of particular interest to us:
"As long as there’s an opportunity to make more fighters, I want to push the record further. As long as I can please someone with the addition of a new fighter, then I believe it’s best that I continue working on the game."
Sakurai knows how popular Geno is and how many people he would be able to please with his inclusion. This line in particular makes me feel just a smidge more confident in his chances. I really think Sakurai and Square aren't roadblocks in any way. It's all up to whether Nintendo would add him or not, and after Banjo, I think there's a chance that they would consider Geno.
Here's hoping!