You've basically just made a list of almost all of the German Musikexportware that makes me cringe
Falco has always been really progressive and unique for his time and I still like many of his songs. The stuff that's been flooding Die Hitparade back then, though, not so much my cup of tea.
I don't know if looks have already been as important back than as they are today, but looking at your list it almost seems that way. Or maybe it's because it is easier to relate to a love song or a catchy tune in a foreign language than a song that speaks to you because of its words.
Marius Müller Westernhagen has been HUGE here in Germany when I was in my teens. Sadly, he retired a while back and, to my knowledge, has very rarely played in public since then.
If you're old enough to remember the old Schimanski Tatorte, you may remember, too, that there have been two movies. The song by Klaus Lage was written for the first movie "Zahn um Zahn" and is a pretty good recap of it.
As for Doro Pesch - I pretty much grew up with Warlock (her original band) and love that she is one of the very few women who's managed to make a name for herself in the metal world!
I don't want to clutter this thread with too many weird German songs that nobody but a handful of people here are able to understand, but if you're interested, I'll give it a thought and privately send you a couple of links to songs that I liked and that probably haven't been too popular outside of Germany.