If a menu item has empty label for one of the languages, then it should not be shown, as it is in the latest version, instead of showing a list of available languages for that item, as it used to be. The latter never made sense to me, since menu are pre-configured once and they are part of the original configuration, they do not change dynamically, like posts. So, telling a user which languages are available for menu item makes no sense to me. It is much better not to show it at all, which gives an admin an ability to temporarily hide a content branch which is not yet ready in a specific language.
As a side effect, it also solves @schenkz problem, since she/he can now create a few menu items with different external URLs and only one of them will show up which has a non-empty label for the current language. She/he would put a label for one language only in each such menu item, while leaving others empty. It is not one menu item which shows different URLs for each language, it is a few menu items instead, one per language, but only one of them shows up depending on the language. Does not it solve this problem?
It also solves @xseon problem, because she/he can assign an empty label to a category menu item for the language, which is not to show up. Menu labels for category items are separate from category items themselves. Category will still exist as a single entity, but menu label for an item showing that category may have an empty label, and will not be shown then. Does not it solve this problem?
Thanks a lot.