Having just started tucking into divinity 2, The jankyness from having movement still tied to 30fps is really jarring and unpleasent (even if you can unlock the framerate to up too 100, it only really affects animations, movement is still decidedly jerky and unpleasant), will original sin be made to run at 60fps natively? It really makes a world of difference to the enjoyability of games i'm afraid.

Movement isn't tied to 30 fps. The original release of DKS introduced a frame rate cap because that helped the stuttering some people experienced in D2:ED, but a patch added the option to change or remove the limit, since it didn't help in every case, and the lower frame rate was an issue for people who never had any stuttering.

Original Sin is using a different game engine. I don't recall any official mention of a target frame rate.