I know it's just a preview but it's hard not to get an assumption about how this movie is going to play out based on Man of Steel, Batman v Superman, Suicide Squad ... and reactions from Justice League and Wonder Woman.
I don't know where to begin with the Justice League trailer. The visual effects and style feel out of place or just wrong. I'm not a comic book purist. I don't have a high expectation about how these characters are (except Batman to some extent from past movies, cartoons, games, etc)
Flash's suit reminds me of something out of the Power Rangers movie from the mid-90s. It's some flashier (no pun intended) version of a rather subdued suit seen in the TV show. Cyborg almost looks like a Transformer made love to a discarded Iron Man suit.
I mean, to their hand, they at least offer something that looks visually unique to the Marvel films. It just doesn't do them any service.
Does Snyder cut these trailers or is it handled by a marketing department? The "I hear you can talk to fish" line ... which almost looked like Affleck couldn't say with a straight face, didn't resurface in the trailer.
Gal Gadot and Milla Jovovich should have a staring contest. I know the latter isn't in these films but she's another actress that literally has one visible facial expression. To Milla's credit, at least her English is comprehensible.
Having Superman not show up in these trailers is a good thing. I mean, he's "dead" ... Comic book way of saying he's taking time off in Tahiti and will resurrect eventually.
Lastly ... I'm pretty sure the guy that played Danny Rand in Marvel's Iron Fist would have been a better casting pick as Aqua Man in a physical sense. He reminded me of Jason Momoa but had more of the physical characteristics I've seen in comic book and cartoon adaptions. Anyway ... Aquaman is the only character I didn't have a problem with. Despite the redesign from his more contemporary look, I liked Momoa in Stargate Atlantis and think he's generally good at being a badass. He struck me as possibly being the fun character in this film.
I'm up in the air about Affleck's Batman. His Arkham Asylum style fight scene in BvS was fun. Do not care if he straight up murders people. I thought the glove's off approach and no kill rule from the other films being dropped was great. It's just up in the air on whether the good bits of Affleck's Batman will ever grow out and become their own thing in a standalone movie.