This is on the mouse-over condition,

You can click on "Configuration" to be taken to a do-next screen/page.

That "I" understand but to a new user this might get frustrating to see the menu disappear and not knowing how to keep it and scroll down...

I'll have to think on this. I don't know of an easy solution. I could simply not make a menu appear if more than x items exist, forcing the user to click on the parent and thus have to go to that screen. But I can think of a few reasons not to do this / how this would frustrate users for other reasons.

Ideally we would switch to using mega-menus. But that would be a major theme project. Not something we have time for in v11.0 but maybe a later minor version of 11.

Best solution I can think of is for menus to be click-activated instead of hover-activated, and then disable disappearing the menu if the cursor moves away (instead make it disappear if clicking outside the menu)

Suggestions are welcome.

The subitems consist of standard config categories, and other links. Some of the other links could be moved...
- Installation Options -- probably leave where-is
- Configure field filters -- could move to a new Advanced Configuration module and no long be shown from the start screen for the admin_config module
- Configure breadcrumb overrides -- ditto
- Configure advanced banning -- ditto
- Composr upgrader -- Probably should just move out to the Tools menu and no long be shown from the start screen for the admin_config module
- Code editor -- ditto
- RSS/Atom Feeds -- Probably should just move out to the Content menu and no long be shown from the start screen for the admin_config module