[discussion] extensions system upgrade

Hello
I'm developed many extensions, and will do many more, so I know something about it
Sometimes I have problems. Usually is missing hook, but there is different topic for it. I'm planning to write a extension(s) witch will let you to:

1. Use some hook more than one time in one extension (but with different priority)
It can be used, when you're using one hook to do same thing in multiple extensions and you want to prepare data first, then output all together. I think it could be added to core.

2. See extension notes always. Now when you are missing some dependencies, and there is info about it in notes - you will not see it.
It should be fixed in core! Or maybe I'm missing some way to do this?

3. Add new optional manifest tag parser, which will store extension upgrade url. It will let advanced extensions developers to "push" updates. They will be able to prepare update, put it into web, and since then other forums admins will see new version and will be able to update it by one click (just like repository is working).

4. Analyze installed extensions and tell you which extensions are sharing hooks (in case of conflicts)

5. Hide unused not installed extensions. Sometimes you have not installed (or uninstalled) extension, but don't want to remove files from server. It's sticking on top and annoying you. (of course hidden ext. will be displayed on bottom of ext. page - like repository)

What do you think about it?