I do agree that (having watched it since it started) that it is sadly now only a ghost of it's former funny self.
As you say,when someone dies they just "shove" someone else it to replace them (often not successfully).
It is (again sadly) becoming somewhat of a TV rest home for aged and faded comedians.
The best thing would have been to have taken it off air when Bill Owen died.Kathy Staff said she was leaving when he died,but of course she didn't.
BTW,the laughter isn't canned.They film it (without laughter) then show the film to a studio audience,then add their laughter to make what we see.