I've booked theme view rooms at GCH and have loved it -- not at all disappointed. However, I didn't pay much more for it over a standard room view rate when I booked a package through AAA, or when I booked a package through
Dreams Unlimited using AP discounts. Get some different quotes and compare the differences. The value of the view is somewhat dependent upon how much and when you are in your room.
I usually called ahead a few days in advance to request a particular view (Grizzly peak view with highest available floor for the GCH) and have always got what I requested. I had a DTD view when the GCH first opened (and without making any request) before they charged extra for the view. I liked it also, but some DTD views involve long walks to the elevator. If I booked a DTD view, I would probably request highest available floor not too too far from the elevators. Some of these would also have views of the fireworks -- if you are often in your room during fireworks, you might want to request that. I'd think a DTD view would also be very nice at Christmas time. For DLH, if I booked a premium view room, I'd probably request a DTD view also with a fireworks view, but others like the pool view.
PS -- I never ask for upgrades, but I recently stayed at the DLH with a standard view. I called ahead and indicated a preference for the Marina Tower over the Bonita Tower and got a nice pool view in the Marina Tower.