can't comment on B5 since I watched it so sporadic and disinterestedly.
but I can tell you for a fact that the standard procedure is for the exec. producer (whedon, carter, strazynski, etc.) to plot out the entire season, which amounts to between 4-10 episodes worth of material. of those 4-10 eps, you'll get something like 2-5 actually written by the guy (rather than story by - if any - credits). and of those, they'll typically direct around half of however many eps they actually wrote. so in a 22 ep season, that leaves you with what? at least half the eps written and (largely) conceived of by "other writers." now these "other writers" are usually (almost always) hand picked by the exec producer, so it's not like they don't see eye-to-eye about where the show is going. and sometimes you get writers so in synch with the creator/producer that you can't tell the difference and on other shows (simpsons comes to mind) the writers outshine the creator(s). but still...it's asking an awful lot that at least half the eps of a 22 ep season be handled by a handful of different people, each only loosely aligned with the creator/producer who's actually in charge of the series. same thing happens in 14 episode seasons, it's just that there's so many fewer opportunities so the series is more tightly wound within each season.
edit: of course, all three names I dropped are fairly notorious control freaks.
now if you really</i> wanna see a train wreck, try watching smallville</i>. it's like they decide on a new artistic direction every other week. you can almost see the studio execs & producers altering the next week's episode based on the demographics of the previous week's performance.
whoops! we're down 12% on the females ages 10-17. need more romance in the next ep. whoa! we just went up 30% in males 18-24. let's have another allison mack cleavage shot. what? down 20% across the board? guess it's time to take away clark's "powers" again. wtf
