Thank you everyone for your replies!

Aviatrix-- I've been to Munich before, but not to the airport. I'm an airport-enthusiast (surely, an FT first) and that's a major one I haven't flown into/out of. As long as domestic flights use the same terminal as international ones, I'd do a MUC-anywhere close to Wuppertal/Luebeck.

rotanes-- Hamburg, oh, that should be on the list too! I don't need to see a theme park, but I've been wanting to go since the missed opportunity of EK's JFK-HAM 5th freedom. Is it filled with canals?

nacho-- no car, I'm a public transit buff too. Aviatrix mentioned one can reach the marzipan factory by bus, even though it's not in the greatest of areas, but that's no matter to me, I really like marzipan. Sadly, I didn't try the Toledo (Spanish) version...but Luebeck is the German epicenter for that stuff, right?

Also, so Wuppertal is no great shakes, save for the monorail? Why is that? Besides the Koeln Cathedral, why is that more suggested than Wuppertal?