I'll take this point by point just to make this response a bit more organized:
The phrasing of "this time" wasn't about Smash. That was more "My opinion this time is"...so that's simply a misunderstanding.
Fair enough.
I'm not basing my opinion only on one game. 3rd parties have been in Smash since Brawl. They were arguably a major part of Brawl as well, considering Snake and Sonic were huge selling points for that game. Every character of the 11 we've gotten, echo or otherwise, has been a specific character. No one else has the same name and same ability. They've each had their own personalities and identities. Erdrick, whose title is passed on throughout Dragon Quest is the most beloved protagonist of Dragon Quest, which makes him slightly different as a protagonist. I'd say Erdrick is more like Robin or Corrin.is"...so that's simply a misunderstanding.
In the first party choices you included, only one of those three is a similar blank slate to Monster Hunter. Robin and Corrin have their own personalities. Sure, they're avatar characters. But they aren't the same type of avatar character as a Monster Hunter is.
I'm not trying to say that 3rd parties weren't important in Brawl. I'm saying that
speculation of 3rd parties really started ramping up in Smash 4. There comes a point where the distinction between avatars and generic characters gets really dicey. Correct if I'm getting this wrong, but the main reason you seem to be going against MH in
this point alone is that they don't have a distinct personality.
Why exactly would that prevent a 3rd party from making them into a Smash fighter?
Even the protags like Robin, Corrin, and Erdrick only differ from MH in terms of having a distinct personality. And in the case of the former 2 (
especially the latter one), a personality doesn't equate to a more diverse character. I'd argue that Villager (the one I assume you're closely comparing MH too), has way more personality than Corrin does in Smash, even thought Corrin's is more "defined". Both are unique through their moveset though, so I don't really consider the personality to be a greater factor than the moveset.
I'm not talking about the specific numbers per game. That, in itself, isn't necessarily relevant to my point. My point was that out of the 11 3rd parties that have been added, they have all been their own characters. Now, that could change, but I personally do not think a Monster Hunter will be added as playable. Their music is among miscellaneous series, the most iconic aspect of Monster Hunter is already in the game, and the Mii Fighters (Nintendo's own form of the blank slate) has been able to wear the same armor of a Monster Hunter in the past.
Who says that Monster Hunter can't be just as unique as the other 11 characters? Just b/c they share their title with a bunch of other Monster Hunters does not mean that they can't be a unique Smash fighter (imo).
If they were planning MH DLC, it would be kinda stupid to put their music separately b/c that would kinda be blatant to speculators.
Rathalos being a boss already doesn't stop MH from getting in. Especially considering Joker didn't bring a boss with him. MH doesn't have to bring one either (and considering Rathalos
is in the game already they don't have to).
Mii Fighters can also wear costumes of distinct protags as well (Lloyd, Heihachi, Yu, Minato etc.) Not sure what your point is here.
Anyway those are my points. You're free to agree or disagree with them.
God, I am not used to typing out these long responses....