975 rp skins and quality

[this is my first forum post ever so excuse whatever poor formatting i may have]

I've always wondered why the 975 tier skins have the widest range of affects on champs. it recently came up on my head why skins like ShockBlade , Steel Legion , Muay thai , Mafia , and Popstar all look exceptionally better than most other 975's and had little bits of charm like Zed's idle, Ahri's dance (ctrl+3, seriously why do none of the k/da skins have their choreography in their dances), Lux's idle and walking animations etc.

Now it could just be that all efforts on the art team are being directed to 1350 tier skins, which is great. There is a clear line of a quality jump from almost all 975 skins to 1350 skins, i think the 1st and 2nd gen of blood moon skins really show this, but it makes me wonder where these small details went.

thanks for reading my ramblings