Dear Brad and devs,
I greatly appreciate the efforts that you are doing in updating the game.
However, I think that you should or find a way to free the savegames of the embedded XML data, or, more probably, provide us an utility which allow to update the old xml data in the savegames with the new one.
You can't expect us to start a new game each time you release a patch or an hotfix (I know we are not obliged, but we want, and often need, the fixes in them).
This problem will probably stop a lot of people from playing, at least until next stable release (and who know if they will come back then?).
Furthermore, it seems that this issue is giving problems to your QA also. For example, I can't see any other credible explanation of how your QA could not realize how last patch broke the offensive spells in tactical battles when loading a previous save, but the more simple one: they were not testing on previously saved games, only on new ones. I understand if you have to deny this, but only other possibility is that they are blind 
BTW, speaking of this, I fear that you should re-view the way in which your QA operate. Compatibility and performance issues in patches are bearable, we all know how they are tricky to find (different setups and configurations, and so on), but it is not acceptable that after a double QA check a patch come out with things like the 100%-missing-bows: no QA guy ever tried to play a tactical battle with bows??
I hope that you don't take this in the wrong way, I like the game and you, but I wanted to make as clear as possible that, according to me, one of your priorities right now should be to minimize frustration for players, to keep us playing the game.