I rode Justice League yesterday. I will advocate for its existence and insist that it's actually a great shooting ride when everything is working and firing on all cylinders...especially for a Six Flags park.
I will say that it's best days are unfortunately behind us. Loading took forever as they seem to be running only like five cars on the whole ride, the shooting mechanism was not working (Like all of the lasers were shot at the same direction), the animatronics weren't in great shape (Especially Harley), and the last two screens were lagging hard.
I really want this ride to get the long refurb it desperately needs. The survey that came out earlier this year seems to indicate the park is looking to replace it, which would be a shame. It just needs a lot more TLC and some elbow grease. I know it's not the most well-received ride, but there should be a place for something like this. It's literally the only indoor ride with air conditioning....something the park is sorely lacking. Heck, I'd be down for them to close it for a while just to bring it back up to par.
I remember the ride being in pristine shape when it opened and it was great. Would love to see them give the ride another chance.