Your sea is normal. Same in Ccom12 as LSH3 by the way.
In SH3, best sea rendering is when you stay at turm’s height.
The more you level up the view, the worst the rendering is

Even others mods such as MEP, Onealex etc...i can show you pictures where the rendering is terribly aweful when taking some heights.
And the more you have high waves, the worst it is.