Maybe its the rose coloured glasses of time, but I still remember with great fondness the commentary of Cyril Towers on the ABC in the 60's and 70's. I think that's why the commentators now disappoint me so much. He was light years better than Kafer, who people seem to think is the best of the modern day analysts.
I too liked Tony Johnson and Phil Kearns commentating together a couple of years ago. For some reason the combination knocked the rough edges off each of them and the outcome was exciting, sensible analysis without the annoying habits. Doesn't happen any more though.
Surely the Executive Producer of the shows should pull the commentators in regularly to discuss their performance and tell them what to avoid. I like scrums as much as the next bloke but Kearns on scrummaging tells you repeatedly that scrumming is wonderful and the only reason people play rugby. It becomes tiresome after the 100th time. He hardly ever analyses the scrum and why it is collapsing/going backwards/wheeling and yet he is well qualified to do so.
Most of the commentators do the easy stuff - commentating on what's there. Very few commentate on what is missing: why forwards aren't cleaning out, why teams aren't using the rolling maul, why the winger is left with no space etc. etc. Yet its usually what is not happening that is the cause of a team's woe's. I think that would add immeasurably to the overall experience.