Hilton isn't my 1st choice of hotel chains and I'm definitely not the most knowledgable about the ins/outs of Hiltons program. But I do know a little about Marriott and they do allow this nice feature and I make use of it quite often as it is very helpful in getting an award reservation if I see one available at a possible future vacation time.
With that said, for a Diamond, I wouldn't have thought this benefit would be a big issue. Doesn't Hilton 'force' award availability for a Diamond even if there isn't any available to others? If so, then just wait until you have the points and then make the reservation at that time. No harm done. Now I could see a possible issue with persons who aren't Diamond level. If they have to wait until they have the points to make a reservation, award availability may no longer be available for the dates they need. That could put a damper on your vacation plans.
