I wonder does this mod affect also textures for water (like in: "maps\_Tex\water\animated")?
Unfortunately not yet affected.
If you enable large textures for water, is it also possible to increase the area that the texture covers on the surface?
The surface resolution is already fairly good; it would be a bigger advantage if we could have a larger texture that covers larger area of the water surface. This would mean that you could fly higher before the tiling becomes obvious, and the water would look better at wider range of conditions (increased altitude).
Increasing the water texture size without making the water texture tile size larger would only benefit the appearance of water at very low altitudes. While this would undoubtedly produce incredible screenshot, the advantages for in-game graphics would be too small to justify the likely effect on performance.
Additionally, if it's possible to edit the water material in such a way, ability to use more frames would be very much appreciated. Currently texture resolution is limited to 256^2 and the amount of frames for the water animation is limited to 16 frames only. With 32 frames, larger tile size (smaller tiling factor) and support for large textures we could do massive improvements for the water in IL-2 1946.
Not sure how viable such changes to the water material are, however.