My beef with BADD is that it seems that its memebers often ignore fundamental differences between dragons. Certainly, GW and Ancient dragons are powerful and terrifying beasts, fully capable of much devious strategy and contingency planning. Certainly, the beasts of fiction fall into this class.
However, not all dragons are very old. Sometimes their mental stats suck, especially when compared to brains of the adventuring party that's attacking them. In all probability, the wizard of the group will be smarter tha the dragon, and the priest wiser - even when dealing with the pinnacles of dragondom. You don't see wizard players being ragged on at message boards for not being the greatest geniuses ever, but, for reason, DMs running dragons have to put up with it. If there's no way the dragon wouldn't know, or have a perfect contingency plan and be able to perfectly predict every possible attack, then what about the 26 Int elven wizard? He should have many of the same advantages. I think it's rather inconsistent for DMs to give dragons a god-like level of knowledge, even weak, crappy dragons, but then not allow players to run super high int or wis characters the same way.
Of course, I agree that most dragons are underplayed - mostly because they have as varied abilities as an entire adventuring party but far fewer actions. I think it's pretty hard as a player to always make the best choice in a situation when acting with extremely limited info. For a DM running a dragon, the problem is even worse, as you essentially have to make choices equal to those of an entire adventuring group, but only has one action. Imagine if you were handed 4 diverse characters of levels and types that you usually don't play, then had to fight in a tough battle with them, but each round you could only use one character. Even when running characters take you know well, that one action per round constraint that a dragon operates under is murderous.
Now fiends seem to be another underplayed monster. They live longer than dragons, have lots of abilities, and little durability. They're like dragons made of glass or balsa wood.
Angry about Incompetent Demons? AAID.
Frazzled by Foolish Fiends? FbFF. FFF