Can a kobold do more than skirmish? Yes. But you have to add some lore!

Tucker's kobolds (Dragon Magazine issue 127) became famous for their combat prowess and their capacity to leverage their numbers. Techniques included more than slinging stones, sneaking about and other guerrilla tactics. Tucker also had them lay traps, plan ambushes and strike from all sides. They added strategy to their tactics. How else could one make the humble kobold more interesting?

Truth is, any group of quasi-intelligent creatures can approximate tactics as Tucker's kobolds. A group of ogres that tend to roll down burning logs from a low cliff can be horribly deadly - and such creatures are stupid as bricks (this may insult bricks, but i digress). A group of kenku, grung or goblins could use the exact same tactical-strategic methods and be just as effective. What goblins need is a way to stand out.

Kobolds Love Dragons! Give Them Dragons

Kobolds love dragons right down to worshipping them. Make this work. This would mean a certain amount of them would be warlocks, cleric-shamans or even draconic-paladins. They would also know how to become half-dragon - they would not only get the ritual to become such but they would do this more rapidly and with less costs than any other creature. They just get how dragon-kin (& dragon-magic) works

In D&D, kobolds are considered part dragon to begin with - so in becoming a 1/2 dragon do they become a half+ dragon or do they become a 'very close to a dragon' humanoid? Are they more draconic than the 'Dragonborn' race? Who knows - but let's see what they can do with this.

Making A Dragon - How Hard Could It Be?

If a kobold increases their dragon-factor to the point where they are almost dragon-newts, how would they finish the process? If they do, they become the very thing that they worship - a worthy goal so long as this is not considered sacrilege. It also makes sense: just as ants and bees create queens, so too would abandoned kobold groups have the means to gain a leader of their own.

How would it work? They could start with the 'urd', kobolds with wings. As regular kobolds don't like them much (inferiority complex apparently) one could presume they don't mind sacrificing them. But what does that look like?

Let us assume all the leaders or officer-equivalent types can get the half-dragon upgrade. They would do this with a special drink and ritual that requires minimal dragon blood and farmable components. Success would be very close to automatic and the half-dragon form (especially for 'small' sized creatures) in 5e does not cause a game imbalance. The optional requirement to gain this form is CR2.

The next stage would probably be more dangerous for the sacrifice-participant to be transformed into a wyrmling. It would require an empty dragon egg, probably repaired by a method similar to the Japanese gold-repair / Kintsugi. They may also etch, embed symbols or runes, paint or otherwise enhance the egg for this process. You may want to make this egg a one-shot thing if it is a common or consumable uncommon item. It it is an uncommon or better magic item / eggshell reconstruction, it could be re-used once a month or so - whatever works for your campaign.

One would presume the process of going from half-dragon-kobold to dragon-wyrmling isn't that much biologically. Instead, the problem would pend more on the number of cultist-kobolds involved in the ritual, the power of the enchanted egg, the expense of the repair-adornment-enchantment put into the egg-shell and so on. You could set the DC very high (18 con save) or even require that the transformed recipient need go through multiple saves for whatever relevant abilities you think best. At the end of it they get a wyrmling - which isn't that dangerous for the first five years.

Assuming a band of kobolds can generate one dragon-newtling or wyrmling per month per one hundred cultists (a newt - 100 kobold x month x 1000 gold), you will be able to make all sorts of adventures.

What Kind Of Dragon?

Each group of kobolds has a natural-majority colour. Once they have dragon-spawn you can give them one draconic paladin, one warlock and a shaman per surviving newtling. If the dragons make it to the young stage you can up the ante and give that tribe-clan both more leader-warriors &/or more powerful versions.

Now you also have resources. Dead applicant-sacrifices that didn't survive the trials to dragon-stage would still be low-grade dragon skin, blood & components. You can now give these kobold tribes appropriate common and uncommon magic items, typically the one-use kind. These would typically be longevity, heroism, extra dragon breath, healing and even specific resistances applicable to the kind of dragon they serve. Longer lasting items may be resistance-granting leather armour or shields, weapons that do small amounts of the draconic damage type or even goggles that provide some version of dragon sight.

Adventures With Draconic Kobolds!

• Survivor dilemma: Two of the newtling candidates survived to become wyrmlings and they do not get along. They manipulate the tribe causing great strife. They appeal to a dragon born (a player character) to help them out. Twist: the two dragons are identical twins / their soul is split / the survivor gets their soul-half back.
• Egg-supplies: They only have half of an egg. They require the materials, magic and recipes to craft more eggshell out of other components (other shells? ceramic? valuable metals? stain-glass window style gold-smithing?). They are stealing these components and are going to do it themselves OR they may ask for adventurer help. Twist: They have all the parts they need for one complete egg - but want to spread out the two halves to make two eggs. This would make for more base-eggs / spawn more draconic wyrmlings.
• Enemy at the gates: Adventurers are sent to put an end to the constant flow of dragon-newt / wyrmlings. OR Adventurers are hired to defend the kobolds as they re-locate whilst keeping their draconic egg brood healthy and safe. Twist: adventurers are secretly hired-patronized by a previously spawned young dragon benefactor that dislikes the new-brood wyrmling competition. This is why their patron knows so much about the kobold base.
• Dragon ghost: An unjustly slain young-or-younger dragon became a ghost and seeks to live again. They seek the help of players to become reborn in one of the eggs should a kobold 'fail' to survive. This may require a special ritual. Also, kobolds may resist if the dragon-ghost is of a different colour than they like. Twist: the ghost is of a metallic dragon and tries to hide their colour-shape.
• Enlightened Egg: Tired of having made enough dragons, the re-usable egg has become sentient and seeks to be re-made into something that doesn't go 'pop' once a month in the goopy dark. The ego seems small but it is charismatic and somehow possesses an adventurer to help with its 'escape' and rebirth. Twist: The last urd-kobold tribute died and uses the egg as a home similar to a Cursed Sword or a Ring of Mind Shielding. It may have Magic Jar / ghost possession abilities.
• Run-Away: A half-dragon Urd-kobold does not want to become a dragon. It is happy with its life, however outcast. It has also gained some powers (sorcerer? druid?) and does not want to give them up. It seeks the party help to escape being tracked by its own clan-hoard-brood-tribe. Twist: The kobold clan has lost too many of their successful wyrmling children to adventurers - this companion urd lies and seeks to discover would-be dragon slayers.
• Pirate Egg: A kobold has fallen in love before she became a recently born dragon-newt. Though he isn't of sufficient power to be eligible, he or she wants to gain levels, the half-dragon ritual and then the egg-slot-ritual. The party will be paid out in something McGuffin they need for their help. Twist: Unrequited love! This now-young-dragon / former lover is embarrassed to admit their kobold origins and seeks to forget and bury everything in the past. It may get messy!