Intercepting document edits/adds/deletes for approval prior to 'going live' - what's the best practice?

[Outerspace Visitor]

Scenario: Our company has various doc libs in various site collections that are accessible by up to several hundred users, many of whom currently have Contribute permissions because we need them to be able to add and update documents in some of those libraries. (After all, this is SHAREpoint; team editing & authoring is one of its biggest features.)

However, we worry that SOME of those users might accidentally, unintentionally, (or maliciously) delete something that should NOT be deleted, and for similar reasons, we also would generally prefer any changes (edits/adds) that they make, to be reviewed/approved by a site 'gatekeeper-editor' before 'going live'.

There is no out-of-the-box Sharepoint permission group that allows add/edit without also allowing delete, so we can't even protect against accidental (or malicious) deletion with out-of-the-box Sharepoint permissions.

It seems like some combination of permissions, version control settings, and Approval Workflows might work, but with so many users and so many sites and libraries, we are not sure how to proceed.

From past experience, we have learned that we are fully capable of wasting weeks of effort, concocting a horrendously complicated, Rube Goldberg-like 'solution' held together by a spider web of procedures, settings, baling wire and duct tape strung across all our site collections and libraries, that might actually work, but would be an impossible nightmare to manage.

Is there a manageable, 'best practice' solution to this (commonly-encountered) scenario?