Then on this, you and I are of one mind. Dragons are the best!
They are far and away my favorite Big Bad in D&D. I am partial to city-buster sized great wyrms whose coming was foretold and whose wrath changes the course of the river of time. I don't use little dragons very often as I feel like it cheapens them, but sometimes smaller and young dragons show up as scions and servants of the Great Beast of the Earth. I usually leave the D&D color assumptions in place, but will sometimes alter or ignore them. I once rana campaign where dragons got their color from the environment their eggs were hatched in, and another time I had dragons change color as they aged.
I've got a proto-setting where dragons are gods(/angels for "ordinary" dragons) and gods(/angels) are dragons. The different types within each brood reflect their progenitor; Tiamat
was once the resplendent progenitor of the
Prismatic brood, but has fallen and gone crazy, shattering her/his mind. (Dragons have a complex relationship with gender.) Nobody knows what happened to the Topaz and Amethyst dragons; they disappeared, rather than becoming Yellow and Purple dragons (and Tiamat never manifested a yellow or purple head). Bahamut is, of course, the progenitor of the Metallic brood, and his/her other unfallen divinity-level dragons are various non-crystalline materials like jet, pearl, glass, opal, coral, etc.
I don't use good dragons very often and when I do it is usually as a patron of the party in the fight against the BBED.
Because I have such an overweening love of dragons, I tried to keep them soft-touch in my campaign. Part of choosing an Arabian Nights styled setting was to avoid things being overly dragon-centric. There's one "BBED"--a black dragon that's been trying to take over the city for a long time, and is close to succeeding--and a good-guy gold dragon secretly hunting the BBED. But that's not the only major threat to the world.
How do you like your dragons in D&D?
Generally, I like them:
- Actually smart. As in, they know they can live another couple centuries at least, so they don't sweat small losses and play a very careful long game. I treat a lot of my villains like this though; the ones that lash out are either specifically linked to being emotional, are outright crazy, or are out of their depth (e.g. druids trying to wrangle with paperwork is never a good idea). Few if any (evil) dragons can be The Starscream, because his chronic backstabbing disorder reveals that he isn't very smart.
- Magnificent. Dragons are THE "you magnificent bastard!" opponent. They need to be charismatic, absolutely ironclad in their confidence, and refined in their bearing. Sniveling weaklings and plodding idiots don't make it as dragons. So if one has reached adulthood or beyond, then that dragon has been tempered by fire and sharpened by time into a blade as sharp as it is elegant.
- Scary. You don't screw with dragons unless you know what you're doing. Even the friendly ones should have just a little bit of alienness to them. In my home game, the Druid has experienced an...altered state of existence which allowed him to briefly see things "as they truly are," effectively seeing part of the higher-dimensional nature of celestial beings, and Shen (the gold dragon) is partially of that nature due to how dragons become the kinds of beings they are in this setting. (Less so than the actual-celestial couatl they know.)
- Resourceful and aware. This breaks from point 1 because it's not just a matter of high intelligence, but of leveraging minimal resources into substantial gains, taking "gambles" that pay off, and being informed well in advance of issues. A really well-written dragon opponent should be hard to catch by surprise, and even harder to catch in a position where they have no alternate approach or backup plan.
As you say, child dragons are hard to fit into this because they're unlikely to meet....well,
any of these points. Children shouldn't be
that smart (yet), their childlike inexperience should weaken any magnificence they might have, their weaker stats and comparative lack of experience make it harder to fear them, and resources and awareness are by definition going to be thinner on the ground for a young dragon.