The sea reflects too much sunlight during day (when the sun is high on the sky). Additionally, the waves look too large and high and they seem to be "morphing" into each other, which makes the sea look like plastic and the ground and the objects on it like miniatures.
Here we can see the sea at about 3000 m altitude with almost no zoom at all. The waves look too large and high and they reflect too much light, so the sea looks like plastic and the ground targets look like miniatures:
If I move the camera far away from the Hornet and zoom in, the sea begins to look really cool and realistic actually, because only the wave tops are reflecting the sunlight. This looks superb! Pay attention to the angle of sun:
...but if I zoom in more till I reach the max zoom, the waves become overreflective again:
The effect that can be observed in the first and the last A3 picture makes the sea look like plastic and the ground smaller than what it actually is. Eg. here is comparison screenshot from DCS (the A-10 is about at same altitude and at the same distance from houses on ground):
The world looks a lot larger in the DCS pic despite of the higher zoom, probably because the waves aren't overreflective nor too large or high. The second A3 picture of the series has really very realistic (and cool!) reflections, that's how it should be also in other zoom levels in my opinion.
Here's a pic from A3 where the sunlight isn't reflected from the sea due to the position of camera and sun. The angle of picture is different too, but game world looks much larger still, probably thanks to the lacking waves and reflections: