I agree with you: as frustrated as I get with incompatible saves, it's often more trouble than it's worth if they can be loaded. I'm thinking of even relatively minor things like installing and uninstalling mods on e.g. Bethesda games which is possible to do with existing saves but it really is a case of "on your own head be it": even when attempting to carefully disentangle yourself it can come back and bite you further down the line. BTDT more often than I'd like.
In this case I dare say that the changes between alpha versions are more significant than changing a mod, and even if they did work, not having a clean start would render much of the purpose of an EA rather irrelevant.
