I think when it comes to elbow pads you are looking at two key things.
1. How much do they move on you?
2. How much water do they retain?
My experience says you will get one of these and give on the other.
The pads that stay in place will retain more water and in turn you "may/will" feel the water through your dry layer.
The pads that don't retain a lot of water also don't have a lot to keep them in place. You loose stability and gain anti-absorption.
perfect example would be the NRS vs Level6
See the Level6 pads have a spandex type material all around while the NRS just has straps. The Level6 pads retain much more water but don't move around.
I have the level6 elbow pads, which have provided more than enough protection for me and I like they don't move around on me. I do notice my arms getting a little colder and sometimes more damp.
Friends with the NRS pads don't complain about being colder or damp but they are adjusting their pads in every eddy.