Now, I freely acknowledge that none of my designs are, in real terms, any closer to being built than yours are (since, in the real world, I don't work for Disney ). But, to me a design isn't all that impressive if it ignores some of the challenges that it is supposed to take into account.
Here, we have a very clear design challenge: the city of Anaheim requires noise protection on that lift hill. If they didn't, it wouldn't be there. Noise blockers are *vastly* more effective closer to the source, as I have already illustrated. You seem to be willfully ignoring the geometry of just how much additional area would need to be blocked from that far away. Yes, it would look better not to have anything over that lift hill, but I doubt there's anyone over at WDI who would say, "Man! Remove the first lift hill tube! Why didn't I think of that?!"
And, to be somewhat picky, sound *can* fly over the barrier in a manner of speaking: the basics of wave propagation state that once a wave form traveling in either 2 or 3 dimensional space (like air) passes a partial block, the particle(s) adjacent to that block act as a new wave propagation source (with the intensity and vector equal to whatever energy it received from the original source), so the waves begin to radiate out past the block in a wedge-like pattern. So, in very rough terms, a barrier that went halfway up the lift hill at that distance would only be effectively blocking noise from the first quarter or so.