Some pedantry out of the way first: given your description it is more of a “baffled omni pair” than a binaural recording. Also your file is 4 tracks (thus a large download!), i guess two of the tracks are a -12dB backup.
Now, my very personal “technical” appreciation of your recording: it doesn’t sound bad. It’s not the most breathtaking ocean shore either but nothing to be ashamed of. The overall sound feels a bit compressed indeed, somehow lacking in dynamics. There is some slight wind rumble that could be guilty here. Regarding “hiss” i think it is the sound of foam(?) on sand rather than self-noise. Globally the sound is in line with what i heard of the EM172-based microphones, a bit rough on the highs and having difficulty to cope with too much stuff happening in the low/low-mids.
So i guess to do “better” in your particular case would have been to get the mics a little higher (like 1.5m higher) above the ground, to avoid dense highs of the water and get more of the distant sounds, thus a more breathy, depth-separated recording.
Here is a raw recording i made with EM172 mics into a Sony M10. You can hear mostly the same general “color” as in yours. (This recording has many defects, including insufficient wind protection). The mics are clipped on my jacket at waist level, standing on a pier (in Astoria, OR) water is about 2m under the mics iirc. Some kind of floating dock was attached with chains, birds were further away. Yet there is not much depth in the result as you can hear.
Imho those kind of sounds (wind in leaves, waves, running water) with a dense content are where one can clearly hear the differences between various microphones. The ability to capture very fine transients make a lot for the realism of those situations.
