As a busy person (my wife and I both work, we have a child, and hard time constraints due to teaching obligations, etc.), free time is exactly what I want to schedule as little as possible. I want to spontaneously decide to do a hike with my family, or when my daughter wants to play, I want to be there. There's enough obligations already, free time should be spontaneous and available to family.
It is also a bit annoying that they focus on these features without solving real problems first. Someone already mentioned search, which is (ironically) indeed quite bad. Also, appointment suggestions based on e-mails has very low recall. I especially noticed this since I switched back to Mail.app, which picks up a lot more dates in e-mails.