Seeing as there still isn't any character forums for BBTAG and that this the most relevant thread for this info, I'll post this right here (though mods are free to delete this if game play analysis doesn't belong in a news thread). Just some stuff I found about the P4 cast while playing the beta.
Yu Narukami's revolver action (or P combo as they called it in P4A) is surprisingly similar to what he had in P4AU. He can cancel 4A (old 5A) to 2A and back (or vice versa) and still continue on.
EX: 4A > 2A > 4AAA > Light Zio.
He can then move on to his old heavy chain of 2B to 5A (old 5B) to 5AA (old 5C). The difference now is that the heavy loop is like his light loop so 5A can go to 2B and back (or vice versa) but now if you try 5AA to 2B to 5AA again, only the 5A will come out. It appears Narukami is restricted to one 5AA per string like his 5AAA (old 2C).
EX: 5A > 2B > 5AAA > Heavy Swift Strike. EX: IAD j.5AA > 4A > 2A > 4AA > 5A > 2B > 5AAA > Heavy Swift Strike. (Assists can extend this, Resonance Blaze allows for Super ender)
As far as I can tell, the only changes to his revolver action is that 4AAA (his old last auto combo normal P4A or his Shadow's last auto combo normal in P4AU) is now placed within the same chamber as his 5BB (old 5DD) (old 2D was also in the same chamber but is no longer usable as a normal, only as an assist, which is his back assist, or 4P), his 5AA is now in the same chamber as his 5AAA, and that 2C (his old 2AB) is now the last normal in his string (couldn't be used once he began using persona normals and could only cancel into 2D).
TL;DR: The revolver actions of Persona characters is largely the same as it was in P4AU, only now they can still do sweep after doing their last auto combo normal and sweep is the very last normal you can cancel into in a single string. Minor changes exist between characters but this holds true for the most part.