Well, they look rather blocky to me, without the curves that would be very possible in a map of this size. I think that the major rivers (Danube, Rhine, Elbe, Volga, etc) should be the most refined, with smaller ones being less worked on. Also, I think the Vikings should start in the Norway region, as that is where most of them hailed from. Put some fjords in, and make it more habitable, and that would be a great step forward.