I love Universal, i believe what they are doing is great. i do not feel however, With grand floridian being a 4 diamond, that they should, at this moment, open an 5 diamond. Due to price, land mass, exclusivity (one of the reasons Grand Floridian is great is because their isn't so much clutter around it, wouldn't feel the same being in between RP and CBBR).
People around the world who can only travel once a year (or once every three years) go to WDW, they want to be in that resort, and then spent a day or two going to UNI. although I believe it will change in the next decade, the tendency is still there for visitors to go to WDW. 5 diamond will come, I believe that, but not at their current location