You want every feature of Wordpress, but you don't want Wordpress. Not once in the last 3 years have I had a plugin that didn't work with a newer version. I haven't had to "reinstall" it even once either. Maybe you just need to choose your plugins more wisely, or if you really care about the quality and security of your blog; write your own plugin.

You're not adverse to switching platform entirely and if the comments here are to be followed, you don't mind rolling your own platform. But you can't write your own theme that's compatible with future versions?

I'd say if you pay attention to the capabilities of Wordpress and actually use it as you're supposed to (I've not seen one major security vulnerability that affected the current version, someone can correct me if I'm wrong) you won't find a better fit for your requirements.