Here's a video I did a bit ago showing the variance in coastal properties. I have been coding this segment to be flexible so although it shows random generations, there are parameters which can be edited later for user input.
In this example I control the number of sides in which the continent is covered in Ocean. This will enable players to choose if it is an island, peninsula, coastal, or land locked.
I got the code to restrict the ocean limits so that the ocean exists in one section of the map, and not broken up everywhere. This way bodies of water bleeding off the map in random places do not suggest a broken continent.