Yeah I could see that side being an issue for some people. Doesn't affect me at all, but I could easily see it chafing for others.
I'm still getting used to the lacing system on them. That second to last eyelet is really deep in the shoe. It's also one of those shoes where you have to tie the last eyelet really securely and it will make all the difference in the world. If I leave that part even slightly loose, my heel starts slipping. Definitely not one of those "throw em on and go" types of shoes.
Looking forward to Primeknit versions.