Honestly, I just want another building on my island. I know this sounds more like a personal issue, but it is kinda lame to only have two shops and the museum on your island. I wanted to build a little city and The Roost would fit perfectly to it. Besides, I kinda enjoyed the mini games from New Leaf, even if they were may not such big deals, it was fun to do them.
Otherwise, I would welcome it a lot if it comes back in a updated form, with more to offer than just coffee.