Very good points.
You should add to your list the fact that the map is a mess. For example, in VC the Netherlands is about one fifth the size of Jutland (Denmark's peninsula), whereas in real life Netherlands is larger than Jutland. Not only this is geographically and historically inaccurate, but it's just absurd. Shetland Islands to the north-east of Scotland do not even exist in this game, despite being a very important viking colony in this era. Sweden, home to a large portion of vikings including Ragnar Lodbrok, is completely missing from the game. At the very least they could make an unplayable area for Sweden, like northern France and Pomerania. And speaking of northern France, Pomerania and northern Norway, they look like as some other person said, I quote, "work in progress." I bet there are even more inaccuracies in the VC map, these are just the ones I have noticed in my first 20 minutes into the game.
In my opinion, the DLC as a whole is still playable. But it is geographical and historical inaccuracies like these that greatly reduce the quality of the game and feel as if the people who were making it were either too lazy or just didn't care.