Yesss! Am I the only one here also looking forward to this?
I've been wanting a 2D SK spin-off for a while already, and Homura appearing here is at least a little bit of that feeling! Heard it's the people that developed Arcana Heart that are working on this, which as far as I'm concerned is a good thing!
It's not really "wrong" or anything, I just wish some of the supports had been playable. Them adding in guest characters that have little to nothing to do with Nitro+ on top of that is a little "salt in the wound" as well, I guess. There are also some characters I would've liked to see from things Nitro+ staff worked on, which seems to be all the basis they needed for Saber.
To put it another way... Imagine it like being a much smaller scale version of if the very first Smash Bros. had invited Sonic, Snake, and Mega Man to be playable, while characters like Fox and Yoshi - great, even very popular, but not quite Mario or Pikachu tier characters in terms of popularity - ended up as assist trophies.