Just got back yesterday from MK and the hub is of course in full construction mode. The barriers aren't really blocking anything. You see them but they aren't in the way of the fireworks or light show. The stage shows can be blocked at least partially depending on where you are.
The biggest problem is the box surrounding the statue. If you're anywhere near the center part in front of the castle it blocks sooooo much of your view. It's truly ugly. The photopass people are pretty good at covering it up with your body though.
The biggest problem is the congestion right after the fireworks is pretty bad. With less viewing area now, there's more people crammed into smaller areas, which leads to even more trouble getting clear of the hub after the shows are over.
We could see what they're planning on doing, and it's clearly going to help. We just had to keep telling ourselves "it's all for the best" as we would avoid walking through the castle or even smoker's way to the side due to extra congestion.