A significant number of the good ideas listed here to improve the park feel unfortunately "blue sky"-y to me.
As much as all of this stuff would help, I think it has been decently established that at some point UDX did want more out of this project than what is currently being offered. So I don't believe that they just never considered colored pavement, shade structures, indoor attractions, murals, more speakers and lights and greenery and puppets - the evidence says otherwise. I just think they simply weren't feasible with the budget and time allotted for the project.
If we see an extra influx of cash come in to the resort post-opening, maybe some of these issues could be remedied. But I don't believe it was possible for UDX to offer any more than what we currently have, and anything we'd like to see added would necessarily come at the cost of something that exists in the park right now. Limited resources and all.