The only interactive we have as users is positive (a heart or retweet) vs negative (thumbs down on Youtube, downvote on reddit).
I think a broken heart, </3, essentially as a downvote, could do a lot to make Twitter more of a community that rewards and punishes, rather than just allows people to exist in their own eco-chamber. The politicians of the last month would have likely seen way more downvotes / broken hearts than favs and retweets, and that might have done something for them personally...it's at least worth a test if anyone at Twitter reads this :).