Great idea! This is being discussed on English Wikipedia here:
and Russian Wikipedia here (long url).
Topic on Talk:User Interaction Consultation/Hovercards for non-logged in users
Actual; link here: https://en.wikipedia.org/wiki/Wikipedia:Village_pump_%28proposals%29#Proposal:_Enable_Hovercards_by_default
Happy to know that even though I was behind the curve on suggesting it that it's already being discussed :D