I actually went on to add even more landbridges. I often play England and France, so I wanted their position to be more interesting. What I did was add even more landbridges on the following connections:

Wessex <-> Brittany
Ireland <-> Brittany
Wessex <-> Normandy
North Umbria <-> Denmark
Mercia <-> Friesland
Scotland <-> Norway

So far this has made the game far more interesting. As England, you can't just take Flanders and hold it easily because if you don't protect Wessex the French will invade behind you. They actually managed to drive me out of Wessex in my current game.

I am hoping to see the Danes use the opportunity to invade sometime. It makes England much more vulnerable, which is nice. Also as France, it would mean you have to defend all three of the English channel provinces to be truly safe from England.