Interestingly if the new dark take on The Joker is successful, it may embolden the MCU to put on the silver screen an enraged king who is willing to wage war on surface dwellers to protect Atlantis (turnaround being fair play since Aquaman was shot like a Marvel movie)...
And why stop there, since they've just got back from FOX a team of mutants who go on to form a sovereign state as sanctuary from humans who have gone to the genocidal extreme of seeking to extinguish this branch of evolution. The parallels to anti-immigration movements and the rise of the Islamic State will certainly not be typical Hollywood fare, but let's not forget that the House of Mouse just made the biggest movie in history about a maniac who wiped out half of all life in the universe in a misguided attempt to do good...