How boring. Still, that's to be expected, after all, this is just the mangaka doing his own shit, the reason grand blue was awesome was part because of the art but the biggest reason was because the actual AUTHOR of the story was different. The one who wrote the script, events and dialogue. That guy wasn't yoshioka kimitake, it was inoue kenji, the author of "baka to test".
However, here yoshioka kimitake is writing his own story from scratch. It's very obvious to see that it's very inferior to his previous works, but that's to be expected, after all, he never actually wrote the stories himself before, he just drew them up. He's great at bringing a story into manga format, but he's truly not that good at making his own story. Too bad, but I'll give this manga a miss. People who expect something brilliant like "grand blue" from this guy are deluding themselves and probably not aware of that this artist wasn't the one who actually thought up grand blue. At the end of the day, the art is needed to bring characters to life, but at the end of the day, the story will determine whether or not it's actually great.