The people in this topic need to dial it back. Isaac fans were know for being levelheaded and "chill" compared to most other massive fanbases. Even if there are only 2-4 characters left in the game, you need to realize how much of a phenomenal game Ultimate has been. It brought back every single character, finally brought in Ridley and K. Rool, Castlevania finally got the recognition and content it deserved. The roster is one thing this game should not be criticized about.
As long as Isaac is not an Assist Trophy, there is always the possibility for him to be DLC. We have only two months left until the game's release, and the Direct revealing the rest of the game's roster will likely be at least before then. Just be patient.
However, keep in mind Sakurai has given us repeated warnings about how many characters are left. He first told us at E3 not to expect too many new fighters compared to other games. He then told us after Simon, Richter, Chrom, and Dark Samus were confirmed, that not only he planned to reveal every fighter before the game's release, but also that there are only "a few" more fighters left to show off. He said this before K. Rool and Isabelle were confirmed. With this in mind, there is likely only 2-4 characters left in the game.
Incineroar and Ken are likely among those final two (Ken has actually been leaked), and anyone that knows anything about the Pokemon Company, knows that a Pokemon newcomer is coming even in a limited newcomer scenario. The question is whether there will be another two newcomers after this. There are plenty of candidates for an additional echo (namely Shadow, Octoling, and Impa), and an additional unique newcomer can be anyone from Geno (whom Sakurai has personally said he wanted to see playable) to Elma (whose game was prominent when the roster was being decided).
The unfortunate fact is that things do not look well for Isaac's prospects on the base roster. A possible two slots after Incineroar and Ken, and likely only one of them being a non-echo slot, means an incredibly uphill battle for Isaac to be on the base game's roster. Heck, there is a decent chance that there are no two additional slots after Incineroar and Ken.
At this point, I would not be concerned about whether or not Isaac makes the base roster, but whether or not Isaac reprises his role as an Assist Trophy. If he does not, DLC is a strong possibility especially if that rumored Golden Sun 3DS title is actually happening.
Just do not be angry and have a meltdown if Isaac does not make the base roster. Remember there is always DLC.
