Zack Snyder is one of the most interesting directors we have working now. He was an early pioneer in the "green screen" style of fantasy filmmaking with 300 that really represented the future of filmmaking. We have so many bland-looking movies coming out now, and his are still some of the best-looking. In that way, he's continuing on in the tradition of George Lucas, Ridley Scott and James Cameron, the same way that Peter Jackson and Guillermo del Toro are.
Snyder's an auteur, who is not out there trying to "appeal to a demographic" or pander to the lowest common denominator. His movies feel like unique visions and not faded carbon copies of last year's hit. He's making movies how he believes they should be made, and asking the audience to take his vision as it is or leave it. That gives him the bold individuality and independence of directors like Scorsese, Shyamalan, Nolan or Villeneuve. Yet, at the same time, his movies are not pretentious arthouse fare, which is just another form of pandering in filmmaking.
Snyder is willing to give you deep thinking and big-budget eye candy at the same time, which is something that's been sorely lacking since George Lucas delivered it in all of his Star Wars movies. It's a real rarity to get groundbreaking, visionary imagery married with intelligent, thoughtful content in movies today. I feel really lucky to have Snyder out there. Movies seem to be getting less interesting from year to year, but he's one of the few filmmakers that still makes them feel fresh, unique, original and exciting.
As for Army of the Dead, it has a fresh rating on Rotten Tomatoes, so not everybody thought it was disappointing.
I don't think Snyder has been chasing "sophisticated adult" audiences. Just like Lucas with his Star Wars films, he's simply aiming to give us an entertainment spectacle that isn't dumbed down or simplified. He's making movies from the clear perspective of an adult comic book, sci-fi, fantasy or horror geek. His movies are for people who love historically disreputable genres but think they should be made with depth, respect and intelligence rather than contempt, cynicism and condescension.
As for Eggers, his films don't seem to be connecting with general audiences, with their low audience scores (Cinemascore and Rotten Tomatoes audience rating) and meager box office takings. Northman had a large budget increase over his first two movies, and it looks like it's going to be a financial failure. He seems to be strictly appealing to the arthouse crowd. Giving him a $70–90 million budget and a big marketing campaign for Northman looks to have been an unwise move.