Ummm....maybe I'm in the minority, but that doesn't sound very good.
(Editorialization - I realized about four paragraphs down that I'm going on a tangent into familiar territory. Look for my signal for me to get back into my original point if you want to skip it, but I'm going to finish it)
Like I've said, I spent some time looking into everything the Internet has collected on the Zack Snyder version of Justice League. Since we got a trailer for that movie over a year before it came out (with footage that had to be from Snyder), I think we have a lot more to work with than most movies. And, honestly, I don't think the movie would've been drastically different if Snyder had finished. The Darkseid tease might've been cool. More character (particularly with Cyborg) would've been cool. More connections to the previous story would've been nice.
But, at the end of the day, I don't think it would've made a difference. It's like the Ultimate Edition of BvS. Yes, it was a more coherent story. But it was a story that I didn't actually like that much. Even at 3+ hours, I didn't like the characters enough, and there still wasn't enough context for why these characters were acting so much different than versions of the character that I like. I know this didn't have to be the same versions I grew up with, but I feel like the Snyderverse had issues that just were never going to fly with me.
There can be a version where Batman kills, but in three hours, you have to explain how he got there. There can be a version of Superman who's not just the Christopher Reeve version, but if he's going to have depth and pathos, you have to also work harder to explain his then-more-complicated connection with the public.
There's a version of the Snyderverse that makes sense to me. And I don't even think they needed to add more to the run time. You can tell it in 3 hours, but you have to go through the trouble to do it. In BvS's case, they probably could've cut out a lot of the Luthor/Doomsday stuff. Just making it Batman v Superman is enough - I'm not even 100% sure they needed to be manipulated by anyone - Batman's twisted enough as it is. And I don't really think they needed to team back up to fight someone bigger - if you're going to make it about character, Superman convincing Batman to come back to the light is your climax.
Explain why Batman is so Hell bent on killing Superman - don't make me connect the dots or write fanfiction. Explain it. Make that a character moment. Explain the public's complicated relationship with Superman. News footage and one protest at the Capitol isn't enough. Maybe bring in a civilian storyline where the people explain why the love Superman. Explain that some people are upset about what happened in Metropolis, but show how Superman won them over. Don't kill Superman in his second movie, and if you do, don't have Batman be the one to bring him back. And if you do, don't make him make such a 180 degree turn in logic that his neck should've snapped like Zod's.
********** REPETITIVE RANT OVER ************
Okay, now that that's out of my system. I don't think that sounds very good. The heroes make an attack on Darkseid? They find out how to get there, and they just go? With the help of the Green Lantern Corps? Would they even be cool with the Earth heroes being the aggressors like that? That seems like a very weird plan, and the "go cosmic" angle seems like DC chasing that sweet Guardians of the Galaxy love.
Not only that, it seems to interfere with the original plan. So the Justice League goes on this attack and then gets beat up and captured on Apokalips? Okay....does that mean there's no solo movies during that time? The original plan was to shoot Justice League (a 2 parter) back to back. Was the new plan to shoot Justice League 2 and 3 (now a 3 parter?) back to back? I guess they could still make Wonder Woman 2 since that's a prequel, and Aquaman and Shazam could take place between Justice League 1 and 2. But where would that leave a Flash or Cyborg solo movie? They'd have to wait for the entire Justice League trilogy to release, or would they need to to also be prequels? Would a Green Lantern Corps movie (originally set for 2020) have to wait? Would it be a reaction to Justice League 2 and 3 or a spark for it to happen?
And in Justice League 3, we get the heroes fighting in the Knightmare world? So they failed? Would Lois still be the key? Would they be able to go back and avoid the Knightmare, or would the movie end with Darkseid defeated but the Earth in ruins? Because that seems like the exact thing that happened in Man of Steel just a million times worse.
Don't get me wrong, they could film some cool action sequences in those movies. And Snyder makes fun action sequences that sorta make you forget about plot holes and inconsistencies. But I don't see the Justice League as an invading army. I don't want to see the Justice League win with the Earth left as some sort of horrorscape. I think we got the right amount of Knightmare in BvS. Doing a whole movie in that world seems excessive and would end up doing more harm than good. It'd be like the end of Fringe - spending one episode in this future world where the Observers took over was cool. Spending a whole season in that world was weird, and I didn't like it.
If that was where Snyder was going, I'm glad it didn't happen.