The problem is the same problem that has befallen almost every licensed game ever: The developers and publishers don't care. It's not that it's difficult in the least, any more difficult than it is to make a video game in general anyway. It's just that they're just looking to sell copies solely based on the name and thus don't put any actual effort into making the game itself good. There are exceptions of course, like the whole Batman Arkham series and games that take after it, but for the most part the entire IP could be burned to the ground and these people don't give a crap so long as they make a little quick cash.