What time period are we talking? As you mentioned it as Burgundy-Lortharngia, I would say this would have a lot of old duchies, prince-bishoprics, etc within it. Your map seems based too much on modern boundaries, as I can see you ache even kept both Brabant around. Seems more likely they would be combined, and Antwerp would either be separate or it would be the capital of the region. It partially comes down to when this conglomeration started, and if they kept lands for ages, or regained them later. And the political landscape, of course. There were counties, duchies, numerous land generalities/city states, church lands... it may seem like slicing them all up into compact sizes would be easy, but you would be talking about areas that have had different rulers, policies, and systems of government. I also imagine a state with all this land wuold try to reclaim more from the sea. Not so much for more farmland, as to avoid saltwater flooding the area, destroying crops, roads, and ports.