Hey Jonasgamble !
It's not really all that different than adding any other market, all we need to have is a solid real-time datafeed, and then we can make it happen. We've gotten several requests from our DACH users to add support for European equities, so rest assured this is definitely on our to-do list. Although right now we are prioritizing the essential features (like deposit/withdrawal functionality).
Thanks for the input !