This smacks of a writer without a clear ending to the story from the start. This is an editor's responsibility as well. That's why drawn out manga's like this rely heavily on good artwork to be successful. Unfortunately, it leaves little room for a decent ending. Secondarily, reliance on a tsundere character to help carry the story can be good, but the tsuntsun must be accompanied by a decent amount of deredere. Else, the the character comes across as an abusive bitch that drags the story down as a result.
Great story. Many people who describe this manga have wrong. If you follow the story from his beginning to the ends the end seems acceptable because of the flow of the story. The girls there are not bitches cause had not revealed their bodies. Story for most romantic man