You can always ignore the fluff, if you don't want/like it... however, if you want it, writing it all yourself or referring to your old MMs/MCs is not easy (especially at the table). Besides, well-written fluff may even inspire adventure or campaign ideas -- it has happened to me many times.
This is both true and untrue... Dependant upon the situation.
In the 2e style, where it was all pretty much in one big blob, while at the table this was very untrue. Often I would find myself scanning for a while trying to figure out what the "important" parts were, or missing them entirely. Doesn't matter if I liked the flavor or not, it was there and even if I wasn't currently in a situation that might make use of it, I had to scan through it all to find what I DID want to make use of.
With the 4e style, if they stick to it, and just increase the amount, there's no scanning. I have a section for knowledge, so I know instantly what flavor the PCs might know, I have a section for encounter groups, so I know what other creatures might be found nearby, and I have a stat block with the relevant combat info so I know what it can do in combat.
If they stick to THIS format, but increase the info the non combat areas offer I will be happy.
If they jumble things up, and get the flavor in the way of what I need when I flip the book open at the table- I will be unhappy.
If they give me as MUCH flavor as I got in 2e, but also format it in an easy to use at the stable style like 4e... I will be REALLY happy!
