IMO this manga became stale when Nagisa entered the story. Don't get me wrong, I like her and wanna root for her, but once this manga entered harem territory it proved unable to balance between the girls. Yeah yeah, the title is Gal, so Miku's gonna win. But before Nagisa appeared it had a sense of balance between Miku and Koharu. But now that we're in harem territory, the formula is several chapters with Miku, very few with Koharu, and one or two with Nagisa. It's a shame too, since the girls are not crazy jealous bitches and actually have a friendly rivalry, but it's not shown enough.
The formula for the chapters is also getting episodic: Shinji finds Miku in some not-so-wholesome outfits or situations -> Miku teases Shinji about it -> Shinji awkwardly tries to ignore the tease -> Something happens that turns the teasing situation on Miku -> She gets embarrassed and turns as red as a tomato -> Chapter ends with Miku lovey-dovey with Shinji who tries to brush it off. Rinse and repeat. It overstayed its welcome.