Why are straits in the game?
It has always bothered me that 20000 soldiers with artillery can simply walk from Ireland to England, from Constantinople to Turkey or from the Danish peninsula to Sweden.
This is ridiculous so please, remove straits!
Ireland to England is pushing it and I agree that this should not be a strait. But the other two examples you mention seem perfectly justified to me. Sweden DID actually "simply walk" from the Danish Penisula to Sweden. Admittedly not with 20.000 soldiers, only with 12.000.
http://en.wikipedia.org/wiki/March_across_the_Belts EDIT: Looks like someone beat me to this example.
In general, straits are supposed to represent crossings that are so narrow, that you do not need a real navy to cross them, but can just use comandeered fishing vessels or something like that. I straits could not be blocked by actual navies, you would have a point, but they can.
What we arguably do need are "reverse straits", i.e. boat-crossings that can be blocked by a land army. Arguably the strait between Constantinople and Turkey should be "reversed".