Stuart, while I completely understand your reservations, I don't think we can conclude much about the current state of the band from these little clips. Liam isn't going to be very Liam in this kind of static setting and suddenly bring hugely different elements into mix. I actually like his version of the final bit of DDIO, he did that live during the Lightsleeper tour last year, too.
I don't think Neil will never touch an electric guitar any more: Nails in my feet, In my command etc. Maybe it'll be more like for the Farewell to the World concert, he played a lot more acoustic back then, but not exclusively.
And I'm afraid I think a five-piece band makes as much sense as a four-piece for them, given that they've had a hidden fifth member for the majority of live gigs as long I can remember, albeit not for all the songs on the setlists.
And regarding Mark vs Mitchell, I think Neil was reasonably clear on Fangradio that it wasn't the quality of the performances that he had a problem with, ultimately replacing Mark and Matt, but the lack of inspiration and input when it came to writing new songs.
So as much as I regret losing Mark and Matt, and as much as I dread the whole family thing (and oh boy, I really do): I just don't think this is the time to judge this incarnation of CH. Yet. There'll be an album and live gigs, and then we'll see.