This is just a super nice to have: Custom plugin support. ie: Something to think about during this stage of development as this app matures further.
As the Lemmy community grows, there are new functions that are getting released as separate apps and as open source that would be nice to incorporate into the "core" Connect app. Since our hailed dev probably has a life and a job outside of Connect development, it would be nice to be able to develop features outside of the main branch without causing too many headaches.
From a legal perspective, OSS licenses could be maintained separately from the main code branch which should push any liabilities to the third party developer. (I no lawyer, but this seems to make sense.)
Things like account sync between instances, custom community sorting and listing, blocking management (outside of filters and such) and many other on-a-whim features would be nice to develop on the side. The possibilities are endless. The core app could even stay closed source for now, which is totally cool at this stage.
The best functionally of all is that I could develop, test and YOLO new features myself without breaking everyone else on a global scale. If third party features become decent enough, they could possibly be implemented into Connect "core" at a later time.
I am fully aware this could cause a fundamental redesign of the application as a whole, so there is absolutely no rush. (TBH, I am thinking the implementation time of this request could take a couple of years.) Personally, I am a fan of applications that are somewhat modular so that is my bias.
Cheers, stay happy, stay healthy!