I would say that your snippet approach is a better one, than creating bunch of different email templates. Can you use custom tokens within your snippets for content. This way, your marketing team can just update the tokens and decide which snippets to display, while publishing the final emails.
Let me know if this works.
Snippets are not editable by the end user. If you want to have the end user edit them you need to make them either modules with editable areas (such as rich text) or add variables for the editable elements (such as images, colors, or strings of text).
With the addition of module-level variables now added, I would explore setting up a template with the new Email Editor 2.0. You can lock down styles and crucial parts of code in the email while still allowing your marketing team to customize content.