I'm not the biggest into amine or mangas, although Ive watched attack on titan, HxH, too name a few... and i don't think so highly of Japanese story telling. Its different, has its amazing writing as any other country.
Specifically with Castlevania I'm surprised because I've seen a lot of people comment negatively on the first season of Castlevania... I think this the major shortcomings stem from several things. ( this is speculation)
1. Netflix gambling in this show. They paid for 4 episodes. I believe they established a lot for 4 episodes and introduced a world and 4 major characters. The show was immediately granted a second season with 8 episodes this time. I'm sure a lot more expansion can be made next season.
2. I didn't see any of the action in the show as fluff or mindless. I would argue the bar scene establishes Trevor at his lowest point.... he states something along the lines of "I've fought monsters of the night and never lost to one" yet the audience sees him barely holding his own against some common drunkards in a local bar. He's developing already, as a character and will continue as the series progresses. Give it time
3. The biggest complaint, which I can agree with is music (which i think comes hand in hand with atmosphere). What is Castlevania without the bad ass tunes? Now my speculation is from reading about working with Konami... They aren't easy to work with. Id speculate Konami didn't answer or allow their music to touch this show until they saw if it would succeed. I'm willing to bet we WILL get some version of a traditional Castlevania tune in this series eventually. Maybe not season 2 or even 3. But I assure you it will happen.
4. The story they choose to use was a mix of lore from Castlevania 3 and SotN. They are starting with the earliest/popular Belmont. Which also includes fan favorite Alucard. I think this is a safe choice and if they finish Castlevania 3, they can open up to Simon Richter or even SotN!
These are my thoughts. Overall I take this season as a long pilot of things to come. My mentality is give it a chance without preconceved notions. If season 2 is the same, color me wrong, but i have faith season 2 will be so much better.