I've always been curious why a 10' reach was a problem with Booming Blade anyways, given what you had to do in order to make it a thing. Wow, a creature with normal reach might take some bonus thunder damage. You of course had to be a Bugbear, use a reach weapon (which is usually a little less damaging on it's own than regular two handed weapons), and take a Feat to do this.
Contrast and compare what you can do with Polearm Mastery or Sentinel when using a reach weapon. Yeah, not really impressed. Sure, you could argue that this stunt combines with those, but how many ASI's are you giving up at this point?
Feats should be awesome, given that you get so few opportunities to select one, and that there's a very real opportunity cost for doing so.