Don't get me wrong, I love the new 4E Monster Manual. All those juicy statblocks save me tons of time. I mean, there's 489 of them! But... There's a crappy index. And, there are fewer monsters in it than any other edition (~150 or so). And there's no Terrain or Climate data for any of the monster. Oh, and there's no information on the kinds of treasures usually associated with each monster. And there's no ecology, or lair, or... or... or... oh for fucks sake. Let's just admit it: the new 4th Edition Monster Manual has some major problems. At least when compared to the 3E version. But do the omissions above really matter? Experienced DM's (like myself) will say "No, not really." "I never used that information anyway." or something similar. And this may be true, but I think all this "metadata" is still useful. It acts as a source for the imagination, helps us shape consistent environs for our players, and serves to guide our choices when building encounter tables. Not to mention, of course, that the 3E metadata that was available was hugely useful for NEW DM's.
This post was prompted because I use Encounter Tables. I generally put together these tables for each wilderness area/zone the player may adventure through. Putting these together is a pain in 4E because there's no Terrain information for any of the MM entries. Then it clicked: there's really not much beyond the tactics for each statblock and a couple very short paragraphs of "Lore" for each monster section. Luckily I have a sizable 3E collection, and I find that keep looking back to those older books.
If you were a new DM, and I were to ask you "Can you give me a list of creatures under level 5 that would be found in a temperate plains region of the world?" or "What creatures around level 10 are found in cold, mountainous regions?" These questions would be tricky to answer using the 4E Monster Manual. I'm thinking of putting together a table that summarizes this info for DM's playing 4th Edition who are new to the game.