With the small ships you most definitely have to time the wave action. There are also times where your ship will be heeled so hard over that your shot won't go past 50 yards. You have to adjust course or sails to try and make the shot happen.
I think the aiming system is pretty doggone well done. Very minimalistic yet a good challenge.
I think they can and will make the shots subject to a bit of RNG and thus more challenging, because right now we seem to be firing aerodynamically perfect balls.