Tough question.... They all have a ton of content in various ways above and beyond their playable character reps. But I still feel Sega is the one kinda left in the lurch.
Sega has three franchises represented: Bayonetta, Persona, and Sonic.
Konami has two franchises represented: Castlevania and Metal Gear
Out of all of them, Konami has probably the best argument. We are definitely not getting anything Square-Enix as they have already gotten two DLC characters.
Edit: Square Enix technically only has two franchises as well (Dragon Quest and FF) although they have gotten a lot of love this DLC pact. I would argue Capcom has three with Street Fighter, Megaman, and Monster Hunter.
Basically this.
Anniversaries aren't important for Smash reveals. I guess if they see they're able to announce or release a character close to an anniversary, they might do an effort... but that's it.
Not to say, there are always anniversaries. We could argue Phoenix Wright is CP11 because 2021 is the 20th anniversary for Ace Attorney, to name an example.
Dude Crash hasn't really seen a lot of talk recently. At least not more than other characters. It was certainly true that he always got a lot of talk but since Kazuya's reveal it's not like that situation hasn't changed.
Regarding Crash. I really, really wanted Crash but I feel like his chances are pretty much over. I don't see him being the last DLC type character. We would have likely gotten him earlier.
Not sure if Nintendo didn't want him or if it is a hold-up at Activision.