I'm actually on board with the idea of boutique dating apps that limit population and interactions in this way. I would try one that gave discounts and date ideas ("-$5.00 discount at this particular restaurant, oh, and there's 4 tables left for tonight, reserve a table for your date now through our app").

If you want to get creepy, do analyses of where people might want to go based on preferences or chat content and give discounts/suggestions for those categories. Other broad filters could be "find some place with lots of people". The less intrusive version is just giving a map of places nearby that have discounts available. Make it convenient to share map and website pointers within the app, so people aren't tabbing over to Google maps to look up the place.

For joining, I'd probably keep it application only or by referral. Egregious complaints and police reports get you thrown right out. Balancing how much identity verification against a creepy factor would be difficult.

These kinds of things are a lot more palatable the more of them that there are. There can be other flavors of boutique apps, and you just shop around and apply to ones you like. Did you already go through all 500 potential matches on this 1k user app? Just download another one.