I can point to a feature that has been asked for many many times and we haven’t built - not because we didn’t want to, but simply because it just never rises up the priority queue: https://community.atlassian.com/t5/Trello-questions/Can-I-add-more-color-label-options-to-organize-my-cards/qaq-p/585754
If you read that thread, you can see that our interpretation of priority doesn’t match a lot of user’s interpretation though. This wasn’t really a heated debate (we’ve tried to solve it during our internal hackathons as well, but it just hasn’t made it to production), but I thought it was instructive to show a case where our user’s think we are completely wrong (and have thought this for years). FWIW, based on this thread, it seems like this could be a good paid feature tbh.
The longest running internal debate though for Trello is a concept called “mirrored cards”. Also called “quantum cards” internally - the idea is for a card to exist on multiple boards at the same time. Or it might be described as cards that sync across boards. The implementation might be different but the experience for the customer would be something like “I have this card on my team’s board and I want to see it on my personal board as a reminder to me, but it really lives on my team’s board”. There are lots of tricky questions to make this work, and actually we thought we had worked through almost all of them (and avoided syncing data around all over the place), and after what I think has been probably 6 or 7 years of talking about this, we built it. But the way we architected it didn’t fit with our overall strategy of how we wanted cards to evolve and so we didn’t ship it.
Mirrored cards gets into really interesting questions about what Trello’s product tenets are - do cards always have to live on boards? Can they live on more than 1 board (or do they just appear in other places like shortcuts in file systems do?) Do all boards belong in workspaces? When I change the filter on a board, do you see the filtered view if you are a different user looking at the same board?
I think it’s really useful to ask those questions and understand that you CAN change the answers to them. You just have to recognize when you are making one of those changes because it can be a big bet.