Thanks for your review. I understand your point, let me explain this:
* WooCommerce 2.1 introduced a lot of changes. I (there is no 'they') have only limited time to work on the plugin and to drop WC 2.0 support was the only solution to release a new version for WC 2.1.
* Some features wouldn't be possible in the way they are now without WC 2.1.
* I'm clearly supporting the concept of keeping software up to date. With the auto-update mechanism WordPress took this also a step further.
* It is clearly indicated that the plugin works only with WooCommerce 2.1.x.
* You can still use the old plugin version that works perfectly fine with WC 2.0.
I would be great if you could revise your review. Thanks.