Eh, I guess that's a fair reason. What other games do you play besides the ones you've mentioned? I also play Mario and Zelda games. I have SM3DL and LOZ: OoT3D for my 3DS. I also play Kid Icarus: Uprising and it's pretty much a fun third-person shooter game that can be played by everyone.
And yeah, we can only speculate as of this moment. And back to the characters, yeah, Apollo should return for sure. It would be weird if he's gone after a year of his last case. Phoenix isn't seen with Maya, Pearl or any spirit medium, so he has no chance to contact Mia as of that time, but I don't think Nick needs advice anymore, since he is not anymore a novice, but an ace attorney. :D I saw a picture of Tracy in his locket, just like in Apollo Justice, and I think that's pretty much her "cameo", but it's nice to see her again and her magic panties.
And yeah, no problem. I heard they're planning to make a sequel that isn't based from the games this time, but they'll make their own, though I don't know how they'll put that off.