I finally took the opportunity to watch the show via the hub.
With David Walliams (Friday) the opening monologue felt too long and somewhat forced. I wasn't keen on the background being used during it. His interviewing was fine and played similar to when he hosted Blankety Blank. The end YouTube clip reminded me of the Daily Show's 'moment of zen'.
With John Bishop's Friday show the monologue had moved to the desk, with a different background which seemed too low resolution. It was also worth noting the background no longer changed for diffrent interviews/features. His interviewing was fine as already tested with his show on W.
As others have mentioned I think part of the show's problem is having rotating hosts. What works with one host might not work with the next. The result is that every Monday may feel slightly disjointed add either an existing feature didn't really work with the new host, or there's the appearance of things being tinkered with. Come middle of the week when things are running smoother that host has probably already been slatted in the press due to the Monday, and there's not long left in their run. I dare say it then becomes harder to sign up presenters of future weeks, as illustrated by Mel & Sue.
In hindsight they would have been much better launching the show with preferably a fixed host (or at least only rotate on a fortnightly basis). Also launching in a post-news 10.30pm would have given the show chance to bed in away from the eye of the press, before moving to 10pm a month or so into the run.
"Listen, we've all got something to bring to this conversation, but from now on what I think you should bring is silence." - Rimmer