Hi Piet,
I would say, that some of the best long distance trails in Denmark are the route along the West Coast/Northern Sea (Vestkyststien). The best section is so far between Agger and maybe Bulbjerg or further north.
Another great trail (and short section only) ist the Gendarmstien.
So far the Hærvejen is some kind of pilgrim-route, so it is somehow secial, but it is a little bit boring. The best parts here are right south of Viborg.
For a lot of these paths you will find a german description.
Anne