It's not enough. Not by a long shot.
Note that the letter (which can be viewed here, if the above pic isn't big enough to read) sticks to this "we believe" and "we would like" type language. It never invokes the actual rulebook, nor does it instruct anyone that they must stand for the flag.
Personally, I hope that more players take the knee. Burn it down. Let the NFL serve as horrifying example of what happens when you go Full SJW Retard.
At this point, it would take a hell of a lot more than this to bring me back to watching football. This is one of the most mealy-mouthed, pathetic, whinging bits of dumb-fuckery that I've seen in a while. This doesn't solve anything this just pisses people off. Rodger Goodell should loose his job for this. Hell, he should have lost his job when he did absolutely nothing while that fucktard from the 49's started kneeling in violation of the NFL's own rules.
I was listening to Rush yesterday, and he pointed out "Does nobody even look at the ads the NFL plays during games? Do they really think their fans are the wine and brie set?" More and more I'm convinced that these people got to where they are through a combination of dumb luck and old money, because anyone who's bothered to watch a game, and the commercials during that game, could deduce rather quickly who the NFL fans are and what they would think about kneeling during the National Anthem. Apparently, the NFL owners, and marketing people, and Rodger Goodell, are too fucking stupid to do even that.