When I ride as a passenger in an airliner, I'm always concerned for those passengers who take their seats, and remove their shoes before even leaving the gate. In the most rare of circumstances where a rapid cabin exit is necessary, they probably won't have time and agility to put them back on. That could mean running through debris/fuel to get away from the plane. For similar reasons I would not remove my shoes at all, even in the water. I wore my lifejacket, shoes will not impede my swimming, as much as I'd want them when I reached dry ground. If you're flying a type where door/canopy jamming is a concern, then, like planning by wearing a lifejacket, take something expendable along to hold open the canopy should it be required - I'm sure that the ubiquitous airplane rag could be well suited to that task.