Straight to the point, I an extremely disappointed where WordPress is taking the customizer because it appears they are moving everything from the admin dashboard and squeezing it into the customizer. It should strictly be used for "theme options" only, and it was my assumption that it was to replace third party theme option panels. Right now, we have the Title and Tagline, Background, Header, Nav, and Widgets mixed in with theme options, and it's just getting bogged down and will frustrate users.

If there's one thing that will turn me away from WordPress, it's going to be the direction they are going.