You could really say the same thing about the majority of outer ring suburbs in columbus. Westerville, Reynoldsburg, Pickerington,Grove City etc.. I'd be willing to bet the majority of people live in Hilliard not because they hate creativity and diversity(not that all of the people in hilliard are the same anyways)but because the cost of a house is good for what you get,the school systems are excellent,and the people are fairly friendly and don't seem to be stuck up. Most people would love to buy a house in grandview or bexley,or live in german village or the short north but believe it or not,not everyone can afford a 300,000 dollar home or wants to risk the columbus public school lottery/afford private schools or doesn't want to cram their 3 kids in a 1000 sq ft home for the same price they could buy a 1700 or 1800 sq ft in hilliard. These generalizations are ridiculous.
Yes hilliard isn't an urban wonderland and there are alot of cooler places in columbus but until they get tons of money(have higher tax rates) like dublin/new albany or somehow become an old suburb like grandview,bexley or worthington its going to be an affordable,middle class suburb which is fairly community orientated and has a ton of young-middle age families.It has nothing to do with its residents hating creativity and diversity and finding some bastion of their hatred in hilliard.
As far as the population issue goes,its probably good that the population is slowing down a bit. Hilliard had some very strong growth over a period of time as evidenced by their 3 high schools and probably is just evening out. Also its hard to say whats hilliard/dublin/columbus/upper arlington in alot of areas. There are alot of people who pay columbus taxes but send their kids to hilliard schools and it seems like the developments I'm aware of are in that category.
And yes the sunflower mural situation that you're referring to was ridiculous! Sometimes people who are in charge of "historic" areas take themselves way too seriously.
Westerville actually has some very nice parks and Otterbein University. But I'll will give you that maybe I was a little too harsh on Hilliard.
I should have just called it Dublin-lite.
In all seriousness though, my critique stems from the fact that places like Hilliard were designed and built as "anti-cities" during an era when that was regarded as a very good thing to be. Thus they were intended to be as bland, inconspicuous and conformist as possible, right down to the soft winding roads, cul-de-sacs and little boxes made of ticky-tacky indistinguishable from one to another. That's what I was getting at when I suggested Hilliard rejects creativity and creative people. Maybe it would be more appropriate and accurate to say that it doesn't freely lend itself to them?
I will note that their recent mayor does get principles of good urban design and has accordingly made an effort to build sidewalks and bike lanes to make that area more appealing to younger people. So maybe Hilliard isn't necessarily that far out of the loop with the times and reality. It still doesn't rate high as one of the places where I would choose to live if I had to look beyond 270, but I understand that people have different opinions and tastes, and Hilliard does hold appeal to some who are either looking for the things you mentioned, or conformity. Or both.