I don't think it's such a good idea, who wants version 3.141592653 anyway? The version number is supposed to be incremented by one with every release of the plugin; there's no real use for it anyway, I was actually considering removing it altogether.
Removing it is not a realy smart idea i think since every plugin uses it. I tested it with double and i can just have a WorldEdit v0.1 without like 8 zero's behind it.
But what then if you wanted 0.1.5a? My point is, once you open this, there's no stopping. Do you think it's really that necessary?
The Android people have solved it quite elegantly. All the apps in the Play store have two version numbers, one machine-readable int, that is compared to see if your phone has a new version or not, and one string that is visible to the users and isn't used anywhere else.
And how would you compare a string, then? If you had a plugin that checks for updates for other plugins, it would have no way of comparing.
I'd say, keep the int, and keep it internal; display whatever string to the user (server admin).
My point is, once you open this, there's no stopping. Do you think it's really that necessary?
the GetVersion function is usefull for getting the version of a plugin from another plugin.