You say that like it's a bad thing...
Ok, so three of those four I really have no clue about and don't care, but the fourth makes up for it and then some.
That's completely what I'm expecting.
If you watch the Nintendo store reactions from E3, it wasn't the first parties getting the big cheers. It was Sonic, Ryu, Cloud (especially Cloud). And the veterans who missed 4. So Snake got double the cheers.
It really seems like most companies are branching out their DLC to third parties. I wouldn't be surprised if each of the characters we end up getting is an out-there third party pick. And there will be LOADS of salt. Still, I can't see a fourth-rung somewhat niche Nintendo first party character generating anywhere near as much hype as a third party.
I've pretty well decided I'm not going for the fighter pack until I see who's in it and decide if the completionist in me needs it. Or if any of them look awesome and have great stages. Or if there's someone announced to hype me to the point i stop caring.