There was always going to be a tricky period after the death of Bill Owen, it was obvious you could not replace Compo. Tom as his son didn't really fit because he was far younger than Truly and Clegg, the audience didn't really take to that idea. Perhaps because of Bill Owen's death, the series then moved more towards a collective with several characters being seen more together rather than the traditional trio. Billy then emerged as one of the better characters, but unfairly didn't really get the same recognition as others when he became part of the trio.
I liked Billy and felt that he was one of the better characters introduced in the later years. It was unfortunate when he left because along with Alvin I think he would have been a better option from which to form a new trio. I also thought that in an episode that Bobby Ball appeared in there was a chemistry between the three which I happen to think would have made a decent trio. I'd rather have watched those three together in the last two series than what we got in Hobbo, Alvin and Entwistle.
Philosopher Clegg,
I agree with a lot of your thoughts. I have been through many discussions in the past about ideas of characters for comebacks and if there was really an authentic trio after Compo. Like you, I view the post Compo years as a larger collection of Barmpot characters getting into various mishaps. Billy was a good part of this mix. I still don't see an actual trio (until they tried Hobbo, Entwhistle, and Alvin.
I also mentioned before about the potential of Bobby Ball being a regular member. I recall suggesting that Barry (even though he was married), Bobby Ball, and Billy become a trio. There were in a similar age group.
You suggest Bobby Ball, Billy, and Alvin. Interesting. Although, who would have played the Clegg-type role, and who would have been the third man? To me they are all sort of Compo-type characters.