First off, I love everything about how the animation has developed and I especially love Elsa's design for the second movie more than I can express.
But beyond that, the hug in the second gif is so much closer. The hug in the first one is the kind I give my aunt or people I don't know well when saying goodbye, one that is lopsided where we both know how what to expect without pretext. One that requires no thought or attention to the other person beyond how to line it up.
The second hug however, is much closer. That is a hug that is meant to last a while. It's not a hug in passing. In the second, their arms don't extend to the side, they are reaching for one-another, like they can't wait for the embrace. There is less wasted motion here, despite how slowly they are walking, there is an urgency in their reach. That hug is where you really want to pull the person tight to you, when you don't want to let go. Where you NEED that moment of connection or comfort. It's so much more personal and meaningful.
I don't know if what I said makes sense but that's one of the first things that struck me about this comparison.