Mush as I'd love a dragonlance book, looking at the recent draconic options doesn't scream dragonlance to me. The dragon subclasses and races seem to have little to do with the setting.
They don't -explicitly- scream "Dragonlance" to me, either... But.
If you had to release a Dragonlance Book and had an edict from on high to make Dragonborn more "Dragonlance Friendly" (Since they're a core race and must therefore be available in all settings) wouldn't you take the same steps as those presented in the UA?
No other setting is quite -as- reliant on creating a significant difference between Chromatic and Metallic Dragonborn, after all. Forgotten Realms made them all kind of Dingy brown, Rust colored, or vaguely dark rather than giving them a specific ancestry. Greyhawk could have them in a similar style. Birthright probably wouldn't care, and in Dark Sun Dragonborn would be, like, twisted children of Sorcerer-Kings trying to become dragons themselves.
But Dragonlance is centered around the dragons being opposed to each other as an explicit thing. The whole War of the Lance and all is fought on the back of specifically colored dragons based on whose side you're on. Takhisis and Paladine are really quite explicit in their connections to the dragons for a reason, after all.
Having them look like Metallic or Chromatic dragons would also help to make them visually distinct from the different Draconians, which are of course a different thing.
The Gem Dragon and Kobold changes are just kind of... "There", and there's FR-Specific spells, too.
But with Fizban and the Metallic/Chromatic split... I feel like there's still a chance. Not a certainty, by any means. But I feel like it's definitely a contender.
If they were planning a Dragonlance book, don't you think they would save a Dragonlance spell for the Dragonlance book? Dragonlance material appearing in other books actually diminishes the chances of seeing a Dragonlance book any time soon, IMO.
1) They haven't released a book, yet.
2) Maybe, sure.