I still go everyday but, yah, I don't buy much (mostly gift wrap since I always give new neighbors some wardrobe options, and I like them to be neatly wrapped).
Personally, I'm waiting for more store upgrades. I think it's a safe bet we'll get them. And I'd LOVE if they meant, say, a "deal of the day" type item with a "rare" color variant (like Redd, but daily). New furniture, like rereleases from previous games, would be a dream come true (I miss the alpine set

).
Also, a Gracie store to work towards would be lovely- except, I think Labelle should run it! She already does fashion checks and has grown a lot as a designer over the past few games, and I'd love to see her own store! I know it sounds silly, but Labelle has matured from a kind of snippy designer wannabe to a mature and sophisticated designer. Plus, it'd make her fashion checks have more of a point (maybe you keep doing them until you unlock the store, then you can do more to score coupons?) and they could have Labelle clothing be available more often, PLUS they could release more and even furniture! And, of course, Gracie would stop by occasionally to check on her... AND offer vintage Gracie designs if you manage to pass her extra challenging fashion check

EDIT: OH! And, of course, some of the visitors could get permanent slots- like Leif getting a permanent gardening shop, and Kicks getting a shoe store extension. It'd be swell if those guys weren't so random. In their place, Nintendo could release new visitors like... IDK, Katrina. She never had much of a point but I miss her!
But, yah. The only thing I'm pretty confident we'll get is more shop upgrades. The rest is just what I would do if I was in charge of Nintendo, and I think all those options do have a chance of getting incorporated eventually!