The real question then, would appear to be "Why was the removal of both
akonadi-backend-mysql and mysql-server-core-5.1 required?"
It wasn't that I removed them, the removal occurred during the update process, presumably a missed dependency in the packaging. My solution was to reinstall the packages. Wish I could provide more detail, but I simply updated my system as I do every morning, not paying a lot of attention, rebooted, started KMail and it wouldn't run because the akonadi wouldn't start. My systems are pretty much straight wheezy, no special repos other than multimedia