I am not sure the word radical applies, but the changes that were made make it upgradeable easily, compatible with more devices, and accessible from anywhere much easier... Basically no big changes.
The compatibility is a big thing for me, as well as having it be smoother in touch use... I wasn't impressed with the preview either, but the lower pricing means that more people will adopt, and the market will get better over time since the devs have more access to it. I hope.
So far it does everything that Win7 did for me... Just smoother. Oh and my wife says she likes it better... So that helps.