Jeff, you seem to have the same attitude towards the JLA movie that I do about giant monster movies. My brother and a buddy of mine were incredulous that I liked Jurassic Word, and the last Godzilla movie. They thought they were weak, with poor writing, etc. But, what they didn't understand is that my standards for giant monster movies are pretty low. I want quality graphics, and monsters stomping cities and people. A good story is icing on the cake. Maybe it's because the story-telling of Japan's Godzilla movies (of my youth) was so poor, that I don't mind so much if Kong Skull Island doesn't have Oscar calibre writing. You seem to think this way about super heroes.
I have a much higher standard for super hero movies. And DC has not been delivering. To me, they've made one good movie since the DCEU has begun. That's a dreadful ratio. You're free to be as forgiving as you are, movie appreciation is not a zero sum game. But, you should be able to articulate the whys, and not be so sensitive when someone else picks apart your argument. Otherwise, why post your thoughts for other people to read.
I haven't seen JLA. I refuse to give DC any more money for the tripe they're passing off as entertainment. But, even from the trailers, and the movies that came before, I know this movie is terrible. And many of your points just seem wrong to me. While I agree that a first movie should focus on the League, that doesn't make a shallow threat mandatory. Personally, I wouldn't have chosen Steppenwolf. Darkseid and his minions deserve a trilogy of their own. And Zelf's criticism that Superman shouldn't have been able to drive off the villain alone is spot on. The League becomes irrelevant when one man can do it all.
A movie can have a couple flaws, and still succeed. Marvel has proven that. But, no movie can be riddled with flaws and hope to get widespread applause. It was foolish to allow Snyder to continue on this project when he made two poor movies leading in(mind you, Man of Steel seems like a master piece when compared to the junk that followed). It seems to me that DC doesn't understand their own characters. That's a major, and ultimately fatal, problem. Superman is meant to inspire hope (hence the messiah imagery). He isn't supposed to be the stoic, brooding hero. But, that's what we were given. And what of the stoic, brooding hero we DO love? Well, the JLA is being introduced with a Batman that's at the end of his career. And Robin is apparently dead? That's just mind-numbing stupidity. Why? Because they wanted an actor with name recognition? Are we just supposed to ignore that Ben is middle-aged?
Then there's this whole notion of a trinity. Jeff, if you've been a fan of the League for as long as you say, then you know what an appalling lie this idea is. The Avengers have a Big Three. The JLA never did. When the JLA was first created, it incorporated the major heroes of DC's independent titles. Flash, in particular, was HUGE in the 60s. The JLA was like the formation of the Knights of the Round Table. Each warrior an equal, if not in raw power, than in their competence, specific niche skills, and dedication. There are no newbies on the League of old. That makes the movie treatment of Aquaman, Flash and Green Lantern so infuriating. Instead of honoring the characters that exist in the comics(which is what the fans want to see), they've changed the characters to accommodate perceived popular trends. A tattoed Aquaman that looks more like a heavy metal singer than a noble King. A Flash based on Peter Parker, to add the humor, instead of a straight-laced professional scientist. The erasure of Green Lantern, because they interpreted the failure of his movie as a deficiency in the character, instead of terrible writing. And the shoe-horning of Cyborg, to try and pretend that the League was diverse from the start. Sorry, that's just revisionism. And flagrant tokenism.
Plus, DC keeps putting the cart before the horse. They should never have made a League movie without first doing solo movies for the principle heroes. Joining forces becomes so much more emotionally fulfilling when you know who they are first. Not as an after-thought. Same with Suicide Squad. Imagine that franchise if they'd used villains first introduced in the heroes' movies? Much more rewarding. But, WB wanted big money NOW. Not down the road. They envied Marvel's success, and ironically, they're still beset by envy. They have consistently failed to make movies the equal of their rival. If they can't make a good Superman or Batman movie, they might as well go home.
When the creators of a movie can't respect the source material, then disaster is the more likely result. And from the reviews, both professional and amateur, it would seem that a disaster is what we got. It's great that you liked the movie. But, from your post, it didn't sound like your standards were high. What good is seeing our heroes on the big screen, if they can't get their appearance and personalities right? If the dialogue makes us cringe? If the action is uninspired? That's what I got from watching the trailers. From the reviews, I don't think I would've got my money's worth.