As a new DM back in the day, with a group of new players who had never played D&D before, it was good to know what were rules and what was fluff. Clear rules also meant less time discussing rulings and re-reading the books for clarifications, and more time devoted to playing.
And while we enjoyed the tactical combat part of the game, we were a quite a roleplaying bunch. That the rules were clearly separated from the fluff didn't mean we did ignore the fluff or roleplayed less because of it. I always find it odd when people say that 4e doesn't allow for roleplaying just because it doesn't have rules for what to do outside combat (as if I need rules to know what to do if the characters go to the bathroom...), when it has a lot of advice and inspiring fluff to encourage roleplaying...
It would have helped to know if 4e is really a "failure", as many claim. Because yes, you can say that 4e sold less than 3e, but that wasn't something exclusive to 4e. Every edition until that point has been selling less than the previous one.