Hey Baumz, part of the change involves treating humanoid feet as plastic. Previously, when humanoids would walk on things, we treated as if the friction was the floor object interacting with the same material object, meaning the humanoid had no say on the interaction. Now we tree Humanoid feet as plastic, which makes slippery surfaces less slippery and sticky surfaces less sticky.
I have some details here:
However, the density tuning combined with BodyMover tuning is a bit surprising to me. Try making the FRICTION WEIGHT of your ice set to a high value like 10 - 100 to see if you get the desired result.