Those aren't exactly new features (drag 'n drop or kindlegen's integration into the Previewer). But I guess if people didn't realize you could drag source material onto kindlegen's or the Previewer's icons, then it might as well be new news.
The problem with the automatic conversion of ePubs is that without special consideration, it ignores how to gracefully degrade certain features that may not translate to the plain-jane version of mobi that scads of stand-alone devices still in use are limited to. It may be easy to assume that ePub and KF8 will cover "most of the bases," but the fact of the matter is that there are people out there spending money on something inferior if you don't use Amazon's proprietary media queries to ensure the graceful degradation of advanced features (or at the very least, previewed to see how it looks on devices that Amazon still sends your books to in exchange for money).