Streamline and Power are the two sides of the perfect swimming equation. One without the other is useless.
In any conditions, its the combination of the two along with open water specific strategies (sighting,side to side stability, coperating with rather than fighting against the water) that will help you.
your overall speed i far more improtant than if there is "glide" or not. Someone with an extended glide in the pool is changing speed more often than if that same person begain their stroke a little earlier. in the open water/rough conditions that same stroke would ahve the same speed realtive to the water itself.
Rough water is deceptive as swells and waves have as much movement in one direction as the other. Energy moves through teh water, but the water for the post part returns to where it started in a circular way.
wind and chop is a slightly different matter, but since the majority of people overwork the swim in rough conditions and spend too much energy, the swimmer who remains relaxed and calm will fare better.
In PR last month we had a day weher the swell was not too big but really rough chop and strong surface winds. Most of the time I could not see anything in front of me except a wave, and I had to breath behind my right armpit to find clean water. The cool part was that I barely had to turn my head to the right and the waves and wind would rush over my right ear straming off my face, creating a beautiful pocket of air that was easier breathing than in the pool. Sighting forward or breathing left however was like getting hit int he face with a sledgehammer.
Bottom line...I kept my same stroke i practice in the pool and enjoyed the rought conditions...swim through the waves and chop adn not over them. Marionette arms will give when a wave hits them ike a tree blowing int he wind but once they are in the water its exactly the same as the pool.
yoru forward progress depends entirely on your interaction with what's going on UNDER the surface of the water. waves are merely a decoration on top of the water.
So the bottom line is taht "glide" as far as success or failure in open water is far less important than your maintainable speed, as well as your attitude emotionally about the conditions. I thrive in rough conditions because I get small and sleek and focus on how the water feels under the surface. I swim and peek up at the surface from underneath watching white foam and raintdrops hitting the surface knowing they really have no effect on how I swim unless I get emitionally anxious about it.
Behing a kayaker really helps in this regard. White water kayaking in the pouring rain is so much fun...the water doesn't change at all, only the external environment. Training your brain not to respond to the environment but stay focused on the medium that's important is a big step in mastering open water conditions.