Nor is his heart beating which is where Kon enters the picture, pretty much. Again this is a relationship I would like to see developed further, not because I am such a Kon fan but because it is actually an interesting aspect of Ichigo's powers.I found Rukia's explanation to Ichigo why he shouldn't leave his body lying around everywhere to be hilarious. If I remember correctly it was mentioned that while Ichigo's soul is absent from his body he doesn't even breathe. Too bad this wasn't canon, Kubo really needs to go into more detail about certain aspects of bleach in the main plotline.
The way I see it mugetsu is just a very OP version of getsuga tensho. I mean, it did exactly the same thing - a huge blast of power hits the opponent. Further, mugetsu is black just like kuroi getsuga. The only thing that seem to differ bteween them is size. I wouldn't mind the return of long back hair though, I suppose. His final getsuga outfit is kickass. I just don't see how Kubo can make Ichigo's fighting style varied enough without changing the way Ichigo is currently characterized... Although I guess ONE possibility that can still make sense is that instead of releasing reiatsu from the tip of his blade (i.e. getsuga tensho) he can maintain it for a very strong, two-hand close up blast that obviously will blast his opponent away at connection. That he is charging his sword but not releasing is emphasized by reiatsu glow around his sword. I should send this idea to Kubo right now o/ It would actually be kickass to see a red glow around tensa Zangetsu. It was actually a very long time ago we saw any kind of reiatsu charge glow from Ichigo.I have actually begun to wonder if it would be possible for Ichigo to use Mugetsu or a variation of it without first using FGT.
Also, possibly, some kind of cutting/thrusting move. Ichigo has a tendency to slash rather than cut with Zangetsu (I suppose it is possible to say that getsuga tensho is more of a cutting move unless he uses it in shikai form where it is definitely crushing, you don't cut with weapons of that size, generally speaking, you crush) even though the way the katana is designed actually favors cutting over slashing in some situations seeng a katana is single-edged limiting the cutting angles.
Honestly, I don't think Ichigo even has to get new abilities per se thinking a bit more about this. It would be enough for him to just change his combat style somewhat to something a bit more varied rather than randomly slashing with Zangetsu at every opportunity.