There is the charm of "first time" and our nature of getting bored of samey things. So the first time girl breaks will always be the most impactful. However I personally like the routes more than the "common part" .Let's say having big differences between branching paths isn't that easy, and this game suffers the same problem of many, many others.
Plus we are playing it 3 scenes every month, we have big expectations and hype. While hardcore fans of the game will always be satysfied, avarage enjoyers may not. That will probably be different if you just play the finished game without waiting for it.
I always thought the first part of the game, the so called "common route" is way more interesting and better written than the endings. It may be cause the corruption process was still going on, while it's almost or entirely after the branching.
Another thing is that because we play the game bit by bit we dwell on things more. When reading completed story even if we don't like something, we can just skim over it till we get to part we like. Well if you don't like what is in the update (sometimes it may be only one scene), that is that, you will be upset and likely to voice it - game is still being developed right ? so there is a chance the feedback will be heard.
Finally I believe that at its core netorare is self contradicting. We want the girl to be pure and deeply in love yet we want her to betray and hurt her beloved. We want the dude to be "close" to the betrayal, we want it be palpable, withing his grasp but never realizing it yet at the same time he is supposed to be a normal person /aka not blind/. How do you write believable characters like that ?