All right, let's look at some of the other questions...
Do the audio stories by Big Finish actually improve upon the Doctors themselves, and their companions?
Yes, especially the Sixth Doctor and Mel, mainly by allowing the actors to play the characters as they had been sold to them in the first place. This goes back to the producer problem I originally mentioned.
For example, Bonnie Langford took the role because she'd been told she'd be playing the smart and sassy computer programmer, not a screamer. Guess what happened on TV? But in the audios, Mel gets to be the character that was originally described but never actually done on the tellybox.
Yeah, I speak from experience here, having written her in BF...
Moreover, to anyone who has gone through most if not all of the BF stuff, does your perception of the characters change after the said immersion? Is, for instance, the Sixth Doctor one of your faves because of those audios, or do you like him less because he's not edgy anymore (and similarly for the others)?
Six is definitely improved, as is Mel, and to a lesser extent Five (lesser because I was OK with him on TV already) - and of course Eight actually gets a run of stories, which is an obviously improvement on 40 minutes of screen time. Six is definitely my favourite audio Doctor.
Seven's still as bad though - the R-rolling is worse, but at least the gurning is out.