Pumped for these. I already own the sculpts, but the minis are so good that I don't mind having dupes. I hope they roll in all the older bands in similar boxes.
To answer your questions, yes there have been stat card changes for quite a lot of the individual fighters, and quite a bit of the art on the cards is reused from the original versions. More superficially, the plastic colours have also changed. Oh, and all the Underworlds warbands have been push fit, going right back to the original Shadespire box Thorns of the Briar Queen are one of my favourite warbands, and I'm really excited to try this updated version.