yoda-sama said:

Did the canonical status of the original Clone Wars series officially get stripped? If so, did it go out the window with the Expanded Universe, or sometime before that (in short, explain this canon purge)? Also, does the CG Clone Wars series ever deal with the events directly leading up to Episode III?

The older series went out with the rest of the EU... and no, unfortunately the new series doesn't deal with the direct tie-in events. The continuity if you were to watch them both actually makes about 90% sense. It goes like this:

AOTC

Genndy series Chapters 1-20

New Series

The rest of Genndy

ROTS

Anyways, someone asked earlier if we could think of another reason for the 4k transfer. Maybe a 4k blu-ray? The 4k thing is catching on pretty quick.