On the new lol mobile leak, we can clearly see that malphite has new walk and attack animations, feeling smoother and heavy. Also garen has new animations, and a new recall.
So let's hope that the 10 years anniversary event will include lots of new animations for older champs.
I mean, the 3d model rig can be reused and applied to another model, and animations can be cropped and adapted.
So maybe they are really doing it? Maybe something good for the base game? It would be cool.