As for Tony and The Lamb, I think he gets very attached to how things were at the time and doesn't seem to move on from that. Both he and Peter were the main lyricists in Genesis back then and he begrudged Peter taking on the sole writing for The Lamb.
I agree, that’s what I was thinking when I watched it. I do think that the album may not have been lyrically as interesting if you got a few members contributing words for it. I think the scenes that Peter set out with those words are touching on genius as I see it. The fact that he was apparently sat in another room writing those words whilst the others were getting on with the music itself is also amazing. Considering what he was having to go through in his own personal life at that time makes me think it was amazing that he could write anything constructive and imaginative at all. A credit to him that he managed it. Tony Banks though equally has a dominant influence on the album with his keyboard work which I think he can be justifiably proud of, even though he doesn’t seem to look back on the whole experience with much enthusiasm.