This looked like the most professional open graph plugin of the ones I look at. Thanks for writing the good description.
Would you like to add integration with the Yoast SEO plugin? -- and perhaps other popular plugins that people use. og:description should ideally come from the post / page / etc. meta description supplied by the plugin.
The developer docs on the description page are good, but they could be improved with an example that would be able to be copied and edited.