I don't think the editing was the problem with SS. I think the main problem was that they put the squad against some huge threat more fitting for Superman than a bunch of C-tier baddies immediately after the squad is created.
Like, this movie and the whole concept of the squad asked for a more "intimate" approach. At the very least it needed a first mission against some less powerful, more grounded enemy. Going straight for the bombastic world-threatening monster felt rushed and was a horrible decision.
I mean why are you sending those unpredictable, untested nobodies against this powerful being that is going to destroy the world? Don't they know Batman, Flash and Wonder Woman exist? The Suicide Squad should be facing mobsters. Even the cringeworthy Leto Joker would've made more sense as a villain.
The script is actually aware of this problem, and I think this is why the end of 2nd act twist feels so random and jarring. The twist where the team was actually going to get Waller, not Enchantress, was just thrown into the script at the last minute because David Ayer, probably in those "oh shit I left the stove on" moments just before falling asleep, realized the team actually had no business fighting metahuman threats so he quickly wrote a reason for them to go to the city anyway.
Which still leaves several problems.
1) The speech that Waller gives at the beginning of the film about putting together a team to fight Evil Superman is 100% bullshit. More like "I'm putting this team together for no reason in particular, actually. Hopefully they have a reason to exist some time later in this movie."
2) Why is she even in Midway City in the first place, other than to give the team a reason to exist?
3) Would not a regular spec ops team be more effective at extracting a person from a war zone?
4) The video mentions this, but her sneakiness has no payoff either. She's clearly hiding something from Flagg and her bosses, but we never learn what and it appears to be of no consequence anyway. It's a useless set up. Unless the thing she's hiding is "I'm going to Midway City now for no damn reason. Later, you should probably send in a group of psychos to come get me because I'm fucking dumb." Which leads to...
5) Maybe most importantly, THERE IS NO ACTUAL PLAN TO STOP ENCHANTRESS. The team does go to Enchantress, but only because that's where Waller is and they still want to finish the mission of extracting Waller.
Other movies that have world-ending scenarios build their plot around coming up with a plan to stop it. In Suicide Squad, the plot builds up to getting Waller out of Midway City. The world-ending scenario is just something happening parallel to the actual plot and there's no plan to stop it. It would be like Armageddon if the plan was to send the oil riggers into space to rescue the cosmonaut from the space station, but while they're up there, they may as well see if they can do something about the asteroid too. You know, since they're already there and they had nothing else to do that day anyway.