Kobolds have the dragonblood subtype. What I meant to say regarding regular kobolds is that they are for all intents and purposes *treated* as dragons whenever race comes into play (pg. 39 Races of the Dragon). My bad. Typo! Sorry. Jesus Christ.
DWK are dragon type. They lose the dragonblood subtype. You're not *treated* as a dragon, you are one. You have age categories. You get more powerful as you age. What are dragons that have age categories and get more powerful as they age? True Dragons comes to mind, because it's pretty explicit that lesser dragons DON'T do that.
Tying this into 15 level druid psuedragons.
About 15 levels of Druid Psuedodragons; I see absolutely no problem with this at all. 15 levels of druid *might* grant you a new power or game ability; the ability to get more powerful simply by aging, *maybe*. Depending on when you age and when you get 15 levels of druid, you *might* get more powerful as you age, *maybe*. Timeless body does not *automatically* grant you more stats, or even bring back lost stats.
What that means is, not all druid 15 psuedodragons get more powerful as they age. When I look at MM 210-211 I don't see any age categories for it. Where are psuedodragon age categories located?
Kobolds *without* DWK feat aren't true dragons. They had to get a Feat to even start this discussion. Character advancement can make new things happen, or make you qualify for new feats/classes/options etc. What is shiny and new about that to anyone on these boards?
Also, pg. 4 of Races of the Dragons takes care of all "half-dragon" shenanigans. It specifically calls out half-dragon and draconic template as narrow cases. That means they are specific exceptions.