If you watch, Britt slows up most in the middle of the route at the point that it looks like Keenum is mid launch. I'm not defending Keenum for many of his throws today but this one appears to be on Britt. I think Britt's reaction and the reaction of the sideline - which you can only see part of in that video - say maybe even more than the clip of the play itself.
Doesn't much matter though. For whatever reason, the receivers and Keenum are not getting it done and appear to be all too often on different pages. Does Goff change that? Dunno. Do the receivers assume the ball is not coming their way on long routes? Dunno - sure as hell shouldn't be the
case though.
Could most QBs make an adjustment on that play? Didn't appear that way to
me. Was Britt kicking himself after the play? Sure looked like it.