You say "unflavored oatmeal," I say "blank canvas."
Is there a compelling reason why humans cannot be "proud warriors," the way they are written? Does the game require all dragonborn to be more proud and warrior-like than their human neighbors? Of course not.
Archetypes exist for a reason. They are useful.
You are
very literally being the "we have X at home" mom. Blank canvases do not count. If they did, Tolkien would never have written elves or dwarves in the first place. Because humans can be "gorgeous, elegant relics of a better time, ancient, wise, and more than a little alien" as OSP's Red once put it. Hell, Tolkien
himself did that with the Numenoreans, who lived far longer than ordinary men (several centuries usually) and had special powers and knowledge due to their proximity to Valinor. Yet elves are a staple, so much so that to suggest their removal is heresy in many circles—even moreso than dwarves. Why? Because their archetype has broad appeal, even if players wander far afield from its roots.
The dwarven archetype is not really about discipline. In fact, dwarves are usually portrayed as belligerent and even fractious, with their deferencs to dwarven traditions being one of the few things keeping their society together. Hence why so many stories involving dwarves as a central element add in a conflict which will "shake their society to its very core" or the like. The archetype comes pre-built with the drama of fractious groups who must figure out what to do when one or more of the traditions that guided them are revealed to be false or hurtful.
Any race you can parse as more "soldier"-like, which the dwarven archetype manifestly is not, has previously had at least one of the following characteristics:
Ugly, usually with a Cha penalty.
Stupid, usually with an Int penalty.
Fights as a "swarming horde," no discipline nor skill involved, just brute force (often paired wirh the previous)
Blatantly evil, often with the implication that fascist control is the only way their society could function
Again, "blank canvas" certainly can do anything, but we have races because manifesting specific archetypes as their own distinct form is valuable in itself. Like how sometimes, you don't want a
white canvas, you want a gold one (for sunrise/sunset), or a black one (for night/darkness.) Could you paint a white canvas so that it becomes black as night? Sure. But you couldn't get
Batman: the Animated Series by using dark colors on bright paper. It has the dark, moody atmosphere it has
specifically because it is bright colors on dark paper, averting much of the aesthetic frequently associated with cartoons: there is no light but what the artist
adds to it.
And I think there is value in having the "proud warrior race" archetype manifest in something that involves a cultural self-discipline that isn't reeking of fascism; of the military commander who is cunning and charismatic, rather than "our blood, his guts" or "we have reserves"; of the warrior-poet, the dangerously quiet type; of the warmaster who would write
The Art of War and say things like, "It is only one who is thoroughly acquainted with the evils of war that can thoroughly understand the profitable way of carrying it on." That archetype is often allowed to fall through the cracks. It doesn't fit the drunk pseudo-Scottish engineer trope of dwarves. It might have fit elves, given their associations with wisdom and intelligence, if they weren't presented as fragile, willowy types who see warfare as crass unless it's reduced exclusively to swooshy sword duels. Anything else falls squarely into the ugly and/or stupid category, as noted.
That archetype was under-served in core D&D until dragonborn came along. Now it is quite well served, and brings the simple aesthetic value of "dragon person," which naturally has lots of appeal in the same way that the "ultra-pretty human" has appeal for elves or "literally devilish bad boy/girl" has appeal for tieflings.
