EDIT: Sorry, for some reason I thought this topic was about 'Delta and the Bannermen' ... so all of the following is totally irrelevant discussion of that serial.

I thought I'd leave it rather than have a post simply reading 'Edited: please ignore'.
So, my thoughts on 'DELTA AND THE BANNERMEN' (not 'The Happiness Patrol', which I actually do regard as being one of the very worst Doctor who serials):
I do feel it succeeds very well on its own terms. The contentious element is whether its the kind of serial that should be commissioned for Doctor who. I have a broad tolerance in that regard (I like Love and Monsters for instance) but even I watch it and am somewhat unconvinced it was appropriate.
It's cartoonish. Deliberately. And the production captures that really well. The Bannermen design is sublime. As long as you can get past 'Doctor Who shouldn't be like this' it really is a damn good set of scripts too. Technically they're hard to fault and they have a fair amount of knowing wit.
Unfortunately, it's gone down as a misstep because it wasn't accepted tonally or stylistically by fandom. And although I am an ogre towards perceived wisdom and narrow-minded fans I can have some sympathy for fandom in this case. Particularly as it happened to hit at a time when fandom was very sensitive to the accusation that Doctor Who was a foolish pantomime. I can understand why there would be a backlash.
This many years on however... I give the serial it's due for being well conceived and very well realized and quite a bold story from a new script editor (Andrew Cartmel) who really didn't want to play safe in his attempts to revive the show. And when you do that you find it's actually an entertaining series of episodes.