Here are a few other QoL stuff they should consider:
Structure Construction
There should be a way to "pin" a construction like a "quest" so I know where I'm at material-wise as I gather, instead of having to add up 3 different structures worth of materials on a separate outside of game notepad to track everything.
Island's Cowrie
Really should be a few more things to buy with these, hell make it so you can convert like 1000 to 50 or 100 Seafarer's Cowrie or something. Or as one of the posters above mentioned, use it to improve existing tools in some fashion.
Landmarks
The in-game guide says that "The construction of landmarks has a variety of effects on your island experience" which is just untrue. All it does is increase your Mood cap by 5. If there are indeed other bonuses, please make them more apparent. If its only cosmetic, then change the description in the in-game guide as its confusing.
Edit: Each Landmarks seems to offer the same bonus upfront AND additional benefits per other structures. In the Guide in the Granary section it says that Landmarks will increase the yield of the expeditions. So in short, yes they are cosmetic only (in terms of choosing which to build) but the more you have built, the more benefits you get in the Granary (and most likely other structures as well)
More Minions
Having more minions roaming around would be fantastic, just saying
Orchestrion
Would be nice if it applied to the entire island, since realistically, we spend more time running around gathering than next to the cozy cabin.
Customization
I know its just the first batch of stuff released for it, but right now not much point in visiting friend's island. When maxed out, every island will essentially look the same with only building placement as its main difference. Would be a lot cooler if there was a multitude of customization options to make each island more unique.