Doubt it to be honest, if they're rebuilding Winamp from scratch then maybe. Otherwise, I'd expect it to be built on top of the existing Winamp source code which is all C++ and not extremely over designed CSS and Javascript

The webpage gives me exactly zero expectation that this will be in any way based on the original Winamp.

Furthermore, the original Winamp was Windows-only. For anything like this to be successful today it needs to be a webapp and/or a mobile app, which more than likely means starting from scratch.

Good points about needing to launch on multiple platforms, that might indeed mean it'll be rewritten.

We'll see

Bloated, yet overly simplistic? Maybe this is really just the relaunch of the Zune player