SE generally don't do surprises very much. If you go back in time you find they at least hinted something in interviews or live letters a few times prior to it happening.

The only genuine surprise recently was probably the Fall Guys collaboration, which of course was mentioned in multiple live letters, but it was not predicted prior to that. But that is common with unusual crossovers.

They also did a whole segment of a fan fest showing the technical side of what they have been doing and it did not include this. It was all about improving the shaders, textures, their depth, their polygons (in new areas) and increasing the scale of everything to 1080p so that it can make use of up to a 2060 GPU's graphics, all of which means adding more lights, longer distance shadows and objects such as boxes as well as more realistic looking cloth, metal and fog.

Animations have not really seemed to be talked about much, although we do have animations on gear such as them blowing when it's windy. That fact alone could mean it's possible with hair, but they have a problem which is that in some cases, 100 players can be together in an area and that is why players have far less detail than everything else.