i know it's a bit of a boring answer to immediately only say "it's curren!" so i'll mention some designs i feel are very well realized— designs i look at and go yeah, this is [horse]!
buenachan ‐ even though she bad a beta design i got somewhat attached to, the new design blew me away. it is THE buenachan. i think you look at it and go THE buena vista.
doto - if you've seen any photos of irl dotosan, you would understand. i think it's perfect. they truly have the same soul
fuuchan - irl, fuuchan was an outstanding mare who inherited all the strengths of tony bin. you can feel it here. i feel that her being a fashionista also represented the fact that her stablehand (who was famous for being a rare female stablehand) handmaking her menkos revolutionized giving horses distinctive "fashions" not just to distinguish them on the turf, but as endearment. high girl power.
taishin - look at the real horse irl! it's such a good representation!
opera o - perhaps this may not be a design thing, but i do love that many of her mannerisms may be based on wada jockey (who was ironically no overlord, but a rookie)
gimusan - if you've seen the real life gimusan!!! then you understand!!! both cool and cute elements, which the real life version boasts, have been perfectly captured.
tap - the real life horse was very haughty and stubborn. i look at her face and think yeah, this is a girl who will only do what she wants. it's great.
ayabe - i don't think you can come up with a more representative design. thank you.
kris s - just as handsome and cool as the irl version. i understand.
gurunee - the fashionable and flashy irl horse who was quite elegant and striking was brought to life in the uma version. i could not ask for more.
shatan - i have a plush of the real thing sitting on my desk and a poster i have not hung yet, i like how the real life one looks, so me praising the design is for real 🤣 the newer sbfk is very reflective of how cool and flashy the real life one looked.
zunchan - i like that her look is clearly inspired by the irl regalia the horse wore during yearly ceremonies (i apologize for not researching about this yet). also no reason has many silly episodes, i look at the uma design and think "yes, she looks strong, but i can believe she fell out of the gate in satsuki sho".
sorry for taking so long to answer this!! i didn't want to give a boring answer so i thought about it heavily 🙇‍♀️