As a plugin author, the most important thing is the incompatibility issue. I am more interested to why a user believes a plugin doesn't work and a user who says a plugin is not compatible should be asked to raise a support query. I believe this should also be the case from 1 ratings since they are of no value to a plugin author.

Also, having version numbers isn't really needed. As a plugin author, I want the user to be using the latest version of the plugin and am not likely to support an old version. As a WordPress user, you should always be running the latest version of WordPress.