There is a slight problem with the representation of Sound Toll, which also serves to weaken Denmark somewhat.
The Sound Toll was a flat cash income. Essentially, it did nothing to increase the influence of Danish commerce abroad, but it provided a solid source of income for the Danish kings. So, the most accurate way of representing it would be as triggered modifier for anyone holding both Skåne and Sjælland, giving a yearly income of, say, 12 gold.
It was a toll on trade. The more trade goes through, the more it earns. A flat volume amount wouldn't really work, especially one that's absurdly good early on like 12 gold. If you want to go this route, it should give a flat % of the trade value of the node. I think it's really fine as is though.
I still think they should get stronger ideas somewhere. I mean, look at their ideas.
+1 yearly naval tradition. ... Wooo?
-1 Unrest. Well considering Denmark never really moves out past Denmark-Norway...
+2tolerance of the true faith, 10% church power. Once again, doesn't really help.
I think if you combined old naval traditions to be +1 yearly naval tradition +5% ship durability you could give them a new tradition that might help them stay alive longer. Maybe even something non-military related like 10% trade efficiency.
Their ideas are really good. What those ideas boost is not. Their naval ideas are among the best, if not still THE best, in the game for navies. 5% durability and 50% FL is absolutely nothing to scoff at. Tradition is a great bonus. 15% light ship CA is a bit lost due to being on light ships, but, in a really pressed fight and especially against jerks in multiplayer this is a serious power swing. The problem is simply how bad naval ideas are in general. If you swung those ideas around to make them sorta analogous, 50% land forcelimit and 5% discipline and +1 army tradition would look amazing, yes? That's before trying to translate light ship CA to a land analogy.
The -1 unrest +2 ttf is awesome. Not sure why it's scoffed at. Because Denmark sucks right now and can't expand well, ideas that help a successful nation are wasted? Would Millets be bad on them too? Nonsense.
Want to fix Danish ideas? Make naval ideas actually matter. Done. Denmark has awesome ideas now.