My .02 cents as an enthusiast from the USA.

– Rarity is a huge driver for me to visit. I will go out of my my way to see a sole survivor, a rare aircraft, or something I have never seen. So in that regard less is more.
– I actually enjoy the “charm” of an old dusty, dirty hangar, a boneyard, or the like. Chino has a charm, the USAF annex, the now condemmed Rhode Island museum building…you can feel the history. I dislike squeeky clean places- feels like some richs guys trophy room (old Santa Monica museum for example)
– If a real hanger is not an option I am am fine with a tin shed. I would rather see money spent on getting aircraft out of the elements, than fancy architecture.
– I do not photograph so could care less about lighting or placement. I am fine with the dim lighting at the USAF musem if it keeps the aircraft in better shape for generations to come.
– Open cockpits or proceedures trainers are great.
– I do like a small placard that talks about the aircraft in general, and especially about the specific airframe displayed- where it served, where it was recovered from….
– Docents walk a fine line. They can be a huge asset for casual visitors, but as an enthusiast I prefer to be left alone- I have been hounded by a lonely docent at a few places, and no I didn’t want to hear their stories….
– I recognize that places need to attract more than just enthusiasts, so I can understand the need for a snack bar, bright lights, games/rides, gift shop, side attractions etc, but personally none of these matter to me.