As David Shaw, the head coach at Stanford said 4 days ago in SI...........it won't make much of a difference, it has no teeth, and it's still non-binding:
https://www.si.com/college-football/2017...-nfl-draft
SI: You were among the most vocal critics of an early signing period mostly because of the academic standards at Stanford. The NCAA ended up moving it up two months. How do you feel about that?
Shaw: December is manageable to me. Selfishly, we have a lot of academic things we need our guys to do. We might have a couple, but most of our guys aren’t going to be ready to sign in December, but it’s manageable.
For [schools] who want to do it earlier [than December], it’s untenable. It really is. What the coaches want to do is going to be counterproductive because many of them want to be able to lock up their class. But here’s the thing nobody can avoid: If a young man changes his mind between August and February, he’s going to be able to change his mind, so I don’t care when he signs. That letter of intent is not binding, so he’ll be able to appeal. So you’re recruiting two linebackers and you get both of your guys to sign early in August, you stop recruiting linebackers. In January, when your linebackers coach becomes defensive coordinator somewhere else, they're going to appeal, and now you have not recruited linebackers the entire season and now you have to scramble and get two more guys. Unavoidable. Guys think, ‘Oh, it will be great’ because they'll have guys locked down. No you won’t. They're still 16-, 17-year-old kids, and they might change their mind and when they change their mind, you won't be able to hold them to this contract because it’s not a contract.