As a Hua Hin resident I would welcome more flights into this airport especially if it started a regular flight to the south of Thailand (Phuket, Krabi). My wife pointed out that it is likely it would mainly be used by residents as a tourist visiting Hua Hin and then Phuket is likely to want to fly back to Bangkok after their holiday and not return to Hua Hin.
One negative point is that I’ve heard all this before and instead of more flights we’ve lost the only international flight to Kuala Lumpur and so currently the only place it flies is Chiang Mai.