I don't know why people assume I have these books. Or that I care that much what's in them.
Well, when you make blanket statements about how the game has changed like this:
Feel free to mock and deride any fantasy rpg without explicit monster roles in the rules (i.e. essentially all of them).
without knowing the history of the game, it makes your claim rather specious doesn't it? If you only meant 3e, then you should have said 3e. Since, other than a fairly small slice of D&D's history, we've actually had explicit monster roles built right into the rules.
More to the point, the gradual unification of monsters and PC rules over the editions hasn't made more work; it's simply made whatever work you choose to do more meaningful. Modern D&D monster design allows you to build whatever monster you want; but having those rules available also makes it easy for a DM to learn how to improvise monster stats if need be, and creates a secondary market for people who want premade stat blocks, which seems to be good for business. Giving you more tools hardly forces you to spend hours slogging over twenty books to pick your gibbering mouther's feats. It simply lets you do that easily if you want to. (Whereas in 2e if you wanted to truly customize your monsters you had to hack the system to do so. At least, if what you say is true).
In 2e, you generally didn't bother, because the upgraded monster was right there. You want a Goblin Chief, he's a goblin with a bugbear's stats. Done. No math, no calculations, nothing.
Sure, you can build whatever monster you want. But, in doing so, you force DM's to spend HOURS designing a creature that will probably only last four rounds on the table. No thanks. There's a reason I won't create anything for 3e anymore and only DM 3e from modules.
Um, thanks?
Incidentally, PF retains this basic structure, while adding on some quick build templates for people who don't like doing a lot of customization on their monsters but still appreciate diversity.
Yeah, there's a reason I won't do PF as a DM. They didn't fix my main problem with 3e which was DM workload. Sorry, if I can't get about a 1:4 ration of prep to play time, I'm not interested in running the game anymore.
Having similarly taken a detour into systems without these kinds of guidelines, I can say that it was a breath of fresh air, made my job easier, and influenced what I look for in a monster book for any system: ideas.
Blarg. No thanks. The "Randomly Pick Opponents and Pray" method of adventure design is not something I have any interest anymore. If the game designer is that oblivious to what should make a baseline encounter, again, I'm not interested in the game. I refuse to have entire sessions get flushed down the toilet because the game designer can't properly signpost how stuff should work in play.
I'm just not that smart. Nor do I have the time or the patience to screw around trying to decipher what constitutes an interesting encounter based on an unfamiliar system.