I can see what you're trying to achieve, but let's do that in reverse.
It will make Gold status (which is the most useful level, from what I gather, in the US since you don't get a lot of hotel where diamond recognition would be interesting) something anyone can have for 200$, including additionnal bennies for the odd stay at a Waldorf Astoria.
It will make Gold status less interesting because I guess everyone and his dog will get it, further devaluating it in worldwide hotel. Probably some kind of equilibrium will be found (if it loses any interest people will stop buying it), probably lower than it is now.
Diamond wil le be surpassed by another top level that can only be achieved if staying at Waldorf Astoria Hotel. So if your travel pattern don't take you to the US, you're stuck staying five times in Rome to requalify. Tough luck for Asian members...
I don't see the benefits we (and Hilton, in fact) would get by merging a "waldorf only" programme with HH. They could simply have a "frequent waldorf guest" with specific bennies if needed.