Really interesting idea behind this map! I'd suggest adding some more variation in distance between landmasses and also consider having a landmass that is maybe 4 or 5 times bigger than anything you currently have just for size variation. You have already seemingly hit the poles so I'd suggest pulling the world apart a bit to allow for some larger oceans and provide more room for new landmasses. That is if your role players don't mind you fiddling with the distance between things.