Dragon Types

I don't really like the way dragons have evolved in D&D.

The general trend has been to present them as super-intelligent, super-powerful schemers, which probably explains why munchkins long to play dragon PCs or something like them. With each edition, dragons get smarter, more power, and more controlling. This is in contrast to the way I feel about dragons of old: often a symbol of evil, certainly dangerous, but frequently a slumbering, ancient menace. It's waking the dragon or trying to steal its treasure that triggers its rage, more like a tiny tarrasque in concept than a mastermind. Old dragons are bestial rather than sentient, with an occasional human or dwarf cursed, usually by his own greed.

I also kind of dislike the color/metal classification system. It seems to take out a lot of the excitement and unpredictability of dragons for me. So I have a proposed replacement...

First, I'd have only four types of dragons, to start. This is from an idea I posted in a comment on the Greyhawk Grognard blog:

• Bestial Dragons - the most common sort and the most physically dangerous; cunning animals, basically. Small ones are serious, immediate threats; large ones are ancient legends, awaiting re-awakening. Not all are winged, nor do all have breath weapons.
• Noble Dragons - the primary intelligent sort, restricted to an area known to be controlled by a draconic society. Not very numerous, as smart as humans, smaller than the bestials but otherwise physically similar.
• Sage Dragons - the least numerous sort; dragons with spells. Each Noble Dragon territory has a Sage Dragon leader; there may also be a renegade or two outside of draconic society. Sage Dragon spells are linked to their breath weapon.
  
• Spirit Dragons - an alternative Noble/Sorcerous type for a different, exotic locale; basically, a replacement gold/oriental sort. Smaller in general, no wings but many can magically fly, inherently magical, with a tiered social structure and innate powers gained at specific ages, including invisibility and polymorph. Instead of known draconic territories, the Spirit Dragons are more like a conspiracy, infiltrating and manipulating human society and reporting back to their leaders at their secret court.

Second, I'd randomize their breath weapon and color. Ha! Now the PCs can't just charge in and attack, but must carefully approach and investigate, to figure out what a particular dragon's strengths and weaknesses are. One way to do this is to roll on the 20-sided Geography table -- yes, the Geography table! -- for the terrain modifier or alternatively the event. That gives you 14 possible breath weapons. The color of the dragon will either be related to the breath weapon or to the habitat the dragon is (normally) discovered in: 50% chance of either. So, that green dragon might have a poisonous gas as a breath weapon, or it might be a forest-dweller with an icy or acidic breath.

Spirit Dragons would work a bit different. What I'd really want to play up with them is the notion of an exotic, conspiratorial, elaborately structured society. In fact, I'm torn between calling them "Spirit Dragons" and "Hierarch Dragons". What does everyone else think of those two options?