Most of the "stop and go" issues I saw were due to people not knowing where they wanted to go or what they wanted to do. I never had traffic issues because of cosplayers. Maybe it depended on the area of the floor. Any of the cosplayers that were stopped all moved out of the flow of traffic as far as I could tell.
I just feel like every inch of that convention center is packed. During SDCC, I can easily find a quiet spot. I do it every year. Once I sat on the back steps looking at the Bay for 20 minutes just to get some fresh air. There are other parts that are pretty quiet as well. Plus with the location of the CC, you can leave and find other things to do to get a break. Because of the location of Javits, there really isn't anything else to do unless you want to walk a lot of blocks.
I know it sounds crazy for someone who's been to SDCC to say that NYCC was packed and crazy but that's how it felt to me this year. I mean, this year at SDCC I really had no issues walking the floor. In fact, some days it was almost creepy how easily I could walk around.