I looked into this, and I was surprised to find that what you suggested here is actually already how it works (and how it's been working since mid-2016)

I can't figure out if it was a glitch, or if it was intentional and we simply dropped the ball on communication and didn't make an announcement when we should have - but since mid-2016 when the current pet transfers page was created, pet transfers don't reduce pet stats for high-statted pets.

and I are looking into updating this information somewhere official, like the FAQ or something - and verifying/updating other battle-related information as well <3

You maintain the official battle guide forum topic, correct? It would be great if you can update the part about pet transfers. (Abandoning pets to the pounds has no battle restriction but DOES reduce stats, so that part is still accurate)

Okay, we've decided:

Transferring will have the 30-day waiting period before a pet can battle and will also remove 10% of any stat over 2000.

Pounding will continue to have no waiting period before a pet can battle, but will also remove 10% of any stat over 2000.

-- Previously it looked at HP, and if HP was over 2000 it removed 10% of each stat. Now it looks at each stat individually and reduces any that are over 2000.

-- Nope, no intel, just level/strength/defense/speed/health.

Done!