Just an off the cuff question. I read Faction War and quite frankly, with that canon, a great deal of PS players would hate the results of either of those adventures.
Did these offerings kill Mass Market Planescape, or was it purely a fiscal corporate retrenchment?
DVD came well after things were done with Planescape as far as I recall so that wasn't a killer to it. It's just a rottenly *bad* module all on it's own.
Faction War is unliked to be honest because it changes a lot of things with the Factions, but never got the chance to *resolve* them. Faction War was supposed to be just the opening bid of a three part series, and a number of planewalker members who absolutely *detested* the changes have come around to a different view as they see the potential involved in following the story line. (The factions aren't *gone*, they're gone from *Sigil* - which is something entirely different. Now you're more likely to see faction related plotlines in the *planes* not just Sigil.)
Unfortunately, Planescape died the miserable death of not making enough money on sales - and had been doing that for awhile even before Faction War. As far as I know it was a purely financial decision to kill the line. The timing was bad, but no - Faction War was not what killed it.