I did this race last year and can't compare to 2015. I went out in near the back of the 2nd wave. I had plenty of open water. They had us jumping in a couple swimmers at a time. There was no contact to speak of really. I followed some fast feet for the first half, who starting zig zagging so I swam the second half solo mostly passing people the whole time with a few occasionally breaks if I found some good feet. With the downstream current and sun behind, I was flying. It was pretty awesome actually.

So I guess from my perspective, the seeded rolling start "worked" well. Given how many people I passed though, I think people seeded themselves somewhat aspirationally. So if you want to follow fast feet, I'd line up a little closer to the front than you think.