Calendar&Reminders

I've just upgraded from 10.6.8 to 10.8.5. My first impression is Yuck. Things that used to be neat and tidy now waste enormous amounts of screen space.

Can anyone explain why Reminders was moved to a separate application? This means that there is no single screen to have an overview of my day. The Calendar Day view is a mess of a screen. Notes has been yanked out of Mail, which is fine since it always seemed to me odd that it was there, but Reminders out of Calendar? Why???