Thank you for your comments, firstly I called it the favourites bar as when you open the "more layers tab" and try to add more than 6, it comes up with a warning saying "a maximum of 6 favourite layers can be added", so I just assumed this was somehow a favourites bar of some sorts. I wasn't aware that the favourites toggle allowed you to view your favourited weather stations, that makes sense and is a useful feature I'll use from now on, so thanks for letting me know!
Agree with you on this, I've given your post a like. Personally I think it should be separate to the layers menu however, as the items in the layers menu can only be viewed one at a time, whereas the items in the "favourites bar" as I called it, can be displayed over the top of sea states, or whatever else you pick from the normal layers menu.
Personally I wouldn't mind the submenus, it would add extra clicks, yes, but personally I'd prefer that - however, as you say, a cloud based customized list saved to the cloud where you can name or make your own categories would be the ultimate solution for those who'd prefer not to have submenus.