Assuming everyone plans for game 18 to be a rest game, you're looking at 22 starters taking one game off each over 17 games. So it's a little over one starter per game. Probably less than one starter per game given injuries. Hard for me to get too worked up about that.
I do see another big problem with this, though. If I'm the Cowboys and I'm in a competitive battle for the division title, and I'm about to play the Patriots, or whoever the strongest AFC team happens to be, on the road, I'd be pretty tempted just to sit all my starters and dump that game. Interconference games are the least meaningful for tiebreakers, and I figure we have a pretty low chance of winning a road AFC game against a really good team anyway. Throw that one game and play at full strength against everyone else. That behavior would be good for the Cowboys but really bad for the league.