TL;DR: AdaShima has ridiculous amounts of slow-burn and navel-gazing in every medium, so the only choice you have is the degree of slow burning you'll be subjecting yourself to. And again, I'm saying this as someone who actually likes the damn story.
This is true, and I actually happen to like the novels too. I prefer romance between characters who already know each other, and I also like long conversations, monologues and tangents, which are harder to do in manga. Adashima happens to fall into this niche, so even though I consider it pretty flawed, I'm still compelled to care about it. The anime could iron out these wrinkles and become the best version of the story, but there's no way to know yet.