I think Zack Snyder didn't really do much research into this one. Maybe it's because it's a Netflix thing, I am not sure. There's so much borrowing from several other popular movies that I just wasn't invested in the story because it was all tooo basic and predictable.
You had the Thanos and Gamora moment in there, you are the Starwars Resistance vs The First Order moment in there. You had the Darthvader type figure in there. You had the Kylo Ren character in there. And the worlds looked like something from a Starwars episode.
Also the whole story was just weak, too weak for a director like Zack. I mean we've seen it done so many times from Lord of the Rings, to Game of Thrones, to even The Avengers. You are threatened by a bigger force, so you go around recruiting people to help you fight this force. That's basically it. There wasn't any rich subplot like we see in eg. Dune. Just very basic.
Does it warrant a part 2, I strongly don't think it did. It's lazy writing and directing and shouldn't be encouraged.
All in all, it's an ok movie. It's not bad like some reviews are saying. The effects are spot on, I loved the cinematography. The only drawbacks for me were the weak storyline, the awful fight sequence, the casting could have been better and the all too familiar scenes.