I second Pysern here. Also, Hex really isn't that elegant. It's half spell and half class ability, and the fact it always has a concentration requirement reduces its effectiveness as a class ability. And it probably is too front loaded power wise for a class ability (Eldritch and Agonizing Blast have the same problem, by Warlock 2 you have all of the power you are going to get and spend the next 18 levels wherever).
And yeah, it not working in a silence field is fine for me for the re-application.