I'm not a subtle person, frankly. So if I see a story with a relationship where the guy clearly loves the girl in a more-than-friends way and it seems like the girl feels similarly (even if she hasn't really sorted it out), I like it if they act on those feelings rather than the story leaving things in limbo. Not only doesn't that happen by story's end, we have a .5 chapter with a timeskip in which they appear to be taking steps backwards--nothing said, nothing acted on, but now they rarely see each other any more. The male lead is still feeling uncertain, afraid and embarrassed to say his true feelings. That makes me sad. We can say it's implied that something will presumably happen sooner or later, but as I said, I'm not subtle by nature; I want to see the resolution, the payoff and the happiness. To put it a different way, I like both leads and so I want to see them happy, and what I'm seeing instead is them, while not completely unhappy, certainly somewhat frustrated, a bit anxious, and surrounded by a faint sense of futility, like they'll be forever trapped in this not-quite-where-they-want-to-be zone . . . and at that, for no real reason that I understand.
The sort of vague secondary couple of grumpy guy and cute incompetent girl takes it even further; they've completely lost touch with each other, adding to the general feeling of uncertainty and malaise.
I'll admit it's a matter of taste.