Heniek
[13] Hero
If we take someone from GG then Baiken all the way I absolutely agreeI would like to think they stop with the guest characters (it honestly dilutes the roster as a whole when looking forward) and instead add in a new character to show that the series can stand on its own without the help of a guest character to promote it. If we do ever get a Season 3 then it shows that SoulCalibur as a franchise can achieve enough success without the need of a guest.
Also, I would pick neither of those two since I'd rather see Baiken if it's a Guilty Gear character. (Here's hoping Baiken makes it in the upcoming Guilty Gear game)