I think Berard is a good prospect, but I think Othmann, Sykora, and Perreault are better.
We are heavy on wings coming up through the system, and I don't think there's going to be room for him here. Panarin is signed two more years. Kreider shouldn't be moved, because he gives you something unique. Laf is future top line, if you don't consider him basically there now. Kakko needs a place to play. The three prospects above need a place to play.
You have to move someone, and Berard isn't going to be very impactful buried on the fourth line.
He's young, and you can get more for him now than you can if you wait until he's 23 and has to clear waivers, and you panic and make a deal for a mid round pick at the end of camp because he didn't make the team and you don't want to lose him for nothing, or you let him languish on the 4th line.
Now, if you feel that Berard is a better prospect than Othmann, Sykora, or Perreault, then feel free to trade one of them (or Kakko) instead for the right piece and throw Berard into a future top 9.
But if the Rangers continue to hoard wingers while lacking for D and centers, they're going to end up regretting it in a few years.