I find it interesting that there appears to be an expectation that commentators' will talk continuously throughout the broadcast. This to me is the problem.
Some commentator's, Duffield when he was still on air, Kirby and Harmon for example, feel a need to speak when the viewer has no need to hear them.
I am capable of commentating for myself, sometimes out loud to my partner's annoyance, and appreciate commentator's when they add something that is not visible on the screen or may not be known to a follower of the sport.
The Dauphine coverage I have seen on the internet has been spoilt by the adulation of Wiggins and Sky and the failure to comment on the lack of serious competition given the TT had a major effect on GC.
The best one I heard was that the Sky buses are built on lessons learnt from F1. Two very similar sports!