Im not having much trouble but I am certainly not doing as well as last year with curls.
I have notice a big change in the position of the corner back during this route, they are always ontop of the WR, unlike last year where they would be 1-2yds away (generally).
Last year you could sometimes get it off to a speedy WR at the curl and he would break lose for a or atleast some decent yardage, but for me theyre just a sure 5-8yds.
Before you snap the ball look at what yd marking they are going to execute the curl at and try time it better (the second you see them turn to his that angle thats when I would stab it at them), but at the same time make sure the CB is atleast behind them, a good play to try is the Full House, Wide, Curls play. I generally find that one of the 2 WR's curling will be open.
Hope this helps to a degree