Bit of a necropost, so forgive me, but here're my thoughts on this lil topic here.
- Tenjo's Son: With all the buildup he's been getting, unless we get a twist shoved in our faces and he turns out to be Sena (I wouldn't be surprised), I can't imagine such an important figure - the "prince" of Ikaruga - NOT being playable if he's still alive.
- Torakaka: Unlikely, but she could perhaps be a bulkier (or even "easy mode"?) alternative to Taokaka, not being as fast but being a bit more brutal? Or heck, she could have a different playstyle entirely for all we know. Perhaps, as opposed to a story character, we'll just get her as DLC/an extra? I dunno, but I'd love to see whatever it is.
- Linhua: She's basically the Tsubaki/Makoto/Terumi of CS, and given how those went (and what's happened to Litchi), chances of her being playable are pretty high, I think. For all we know, she might even bust a move as DLC in CS: Extend, but that might be pushing it.
- Phantom/Nine: With Relius getting his plot in in Extend, we'll probably see more of her there, and given how in CS she's already got more role than Hazama/Terumi did in CT, I honestly don't think it'd be impossible for her to be playable. Heck, depending on how the game goes, we might even get both an "evil" Phantom and a "good" Nine as playable characters - though Nine might end up not coming out until BB4, I suppose.
~ Kokonoe + Jubei: I'm... on the fence with these two. On the one hand, they just WORK as NPCs. On the other, though, they're hugely popular, capable fighters, and since things got serious at the end of CS, it might be the kick Kokonoe needs to get down and dirty herself - and Jubei is, well, Jubei.
- Saya: Given her position, I can't see her taking to the battlefield until it really hits the fan, so nothing less than the final boss of 3/a regular of 4/the final boss of 4 would cut it for her, I think.
- Murakumo Units: We're definitely getting a new one - well, probably - the real question is just from where, since Lambda is dead (and never had a chance to develop, poor thing), Nu is either dead or being used to make SOMETHING by Hazama and Relius (depending on how you view the last scene of CS), and Mu ceased to exist (maybe) after Ragna busted up Noel's head. I could see Mu being some freak unlock of Noel's, buried in her psyche or something, but the Nu 3.0 would still need to be restored/built, and who knows? I'd kind of like to see another type of Murakumo myself, given how Lambda/Nu and Mu are so different from each other.
- Bloodedge: Honestly? I'd say he HAS to be playable by the end, be it 3 or 4, since we're either fated with the last game ending with Ragna going back in time to set all of the events into motion, or this happening but through an alternate ending - ala Jin to hakumen. If it happens as a "big ending", though, it's pretty likely Bloodedge would be playable like how Mu was.
And I.... THINK that about wraps it up!