I'm now only 17 pages behind, so I figured I'd tackle another point
Right, but that's already the reality. So your position is already supported.
It's mine that's losing out, and everyone spending 60 pages telling me I'm wrong and a 3 foot tall slim (vs dwarf, thick) being is going to be as strong as an 8 foot tall (seriously folks, go stand beside someone who is 6'8) powerfully athletic being makes sense?
It's a non starter. It's honestly absurd. It's like training children (and I have) and training heavyweights (and I have).
For you, this new system is fine.
For me, it never will be.
I'm not saying you shouldn't get to have your system to tell your stories.
I'm consistently being told 'no it's fine'.
It isn't. It's not remotely close to fine.
So, here is the problem I see with you saying the system will never be fine as presented in this UA.
How big is a Dhampir? Are they 3 ft tall or 8 ft tall? Are they very skinny for their size, or very broad and muscular?
The rules say "small or medium" so, they can range from 3ft to 8ft, from 50lbs to 800 lbs. Therefore, what should their strength modifier be? +0? +2?
What if I decided to play A Dhampir who fed upon the dreams of the living? Should I have a bonus to intelligence? Or to Wisdom? Would a bonus to intelligence still make since if I chose to be a Dhampir who consumed raw meat like a ghoul?
What if my undead nature came from being hit by a blast of psionic energy that killed my body, but my mind was empowered and tried to force my body to still function, even though my heart was destroyed so I cannot pump blood? What if my character is actually a parasite piloting a corpse, who needs to consume various vital fluids and nutrients to maintain the body in good shape? Do those two concepts get the same bonuses?
These lineages as presented cover such a wide variety of ideas, how would narrow them down into a single +2 and a single +1?
Now, you might say "that is one thing, but they said all lineages going forward will be designed this way, that in unconscionable"
But, is it? Aren't there more concepts that work exactly like this? Sure, I'd say the Thri-Kreen shouldn't be treated this way they are clearly a single defined race...
Except the "Kreen" include Thri-Kreen, Tohr-Kreen (with further variants like J'ez, J'hol, T'keech and Tondi ), Zik-Trin, Xixchil, Trin, Zik-trin'ak, and Jalath'gak
Now, I'm not an expert on what all of these differences mean in game, but I'm counting ten to eleven difference variants. That shoudl easily give enough variety to justify some floating scores. Sure, you could make ten to eleven different subraces instead, but it depends on how big of a difference you want, and looking at the races presented outside of the PHB... very few have sub-races. Most are one offs. So, a "Kreen" one-off, with a floating set of scores, could easily cover the entirety of the species, and allow a lot of the more obscure versions that would otherwise be ignored.
So... where is the downside, either here or in the future? That they might have more races like Humans that have floating ASIs? I'm fine with that. Humans don't need to be that unique, after all, there are about half a dozen races that have +2 str/+1 con. And Half-Elves, Changelings and Tritons already have floating scores. Shifters have multiple subraces, each with a different set of scores.
If this isn't about "I don't like Tasha's rules" and is purely about the future or this current ASI... then where exactly is the problem? That they might maybe do something in the future that won't make sense?