I think they are different, but related, things.
That’s perhaps why we have both Mesh Warp and Liquify in Photo and not just one function which does both.
As I see it, Mesh Warp affects each part of the image according to an overall ‘envelope’ (with some parts not being affected, depending on the result) while Liquify affects only a part of the image (depending on relative image/tool size) – one is ‘top down’ and the other is ‘bottom up’, so to speak.
One thing I wouldn’t want to happen is for the discussion about this functionality to get mixed into the discussion about vector Mesh Warp as I think they do different, but complementary, things. I see this as more of an extension to the Node Tool rather than anything else; just a slightly different way of selecting nodes and moving them together (which does sound a bit like vector Mesh Warp but different). Or maybe we could have a Vector Liquify Persona?
Anyway, there are plenty of other things which probably need to happen to the software before this sort of thing is even considered so there’ll be lots of time for discussion. Maybe something for version 3.0, perhaps?