You´re being intentionally obtuse. Nobody knew what kind of show School Days was before it actually aired, which is why it had such an impact on its audience - nobody saw it coming. Similiarly, I disagree that it "was obvious what kind of show" Plastic Memories was. Quite the opposite, I´d say it was to be expected that the drama keeps rising towards its finale ... but that never happened.

When I go into K-On, I expect a dumb girls group-anime. When I go into an anime about concsious androids that only get to live a couple of years, I expect ... more. You´re free to have your own expectations, but don´t call others´ "wrong".