Hyatt allows you to type entire continents or countries as a search field. I’ll typically use this when finding cheap EQN. You can filter to specific brands too. (Not dynamic dates, rather dynamic destination).

As for the UX enhancement, you could probably reach-out to your globalist concierge (if applicable), generalized feedback form on the Hyatt site, or the consumer affairs email. As this is an enhancement (i.e. using their development resources), it’ll be likely be non-existent on their dev list.

If you’re very passionate about it, you could sign-up for some focus groups and hope Hyatt Corp is a client & coincidently is soliciting feedback on their UX… Post comments on the App Store, etc.