I think it would be a neat feature to add a section so that people could use the search bar to suggest card for other peoples’ decks.
The idea is that the search bar is still useable when you are looking at another person’s deck, but it would automatically put any card that is suggested into a tab like the tabs tokens are under, or maybe under a tab like how cards can be moved to the sideboard. Maybe have an upvote system as well with it so if multiple people recommend a card it gets more upvotes.
It could also be limited to mutual followers being allowed to do this, to prevent spamming of content creators pages.