"People not yet using Google+" defaults to all your Gmail Contacts. This is a two-fold problem:
1) Gmail defaults to adding contacts for anyone you interact with. I had 1500 spurious contacts (newsletters, web service email endpoints, e-commerce sites, etc) to weed through. I couldn't easily find my actual friends.
2) There's no way to say "Don't recommend these contacts to me any more", meaning, if I tried to "Find friends" to import a small list, they'd just be mingled into those 1500 useless addresses.
3) There's no link to your Google Contacts to manage who is showing here.
Solutions:
1a) Provide a way to dismiss or not show people.
- or -
1b) Consider supporting a "Show in Google Plus" group in Google Contacts.
2) If doing a "Find friends", have the imported group shown w/o the previous noise. (e.g., add a "People last imported (77)" tab, or a Sort By: Last Updated)
3) Under "more" menu, or somewhere more prominent such as after the "still share with them via email" phrase, add a Contacts link so I can get to and manage my contacts.