In Maverick, most of the Gnome software are version 2.32, but Evolution is version 2.30.3. Lucid also used an older version of Evolution. I think Evolution is getting better and better and makes sense to ship a newer version.
New software needs testing before it can be pulled into a distribution and 2.32.0 was only released right at the end of September, not giving it anywhere near enough time for testing.
Stability is all the more important in a mission-critical applications like Evolution, Firefox and OpenOffice.
This is just how things go sometimes.