For instance, he's got some products in his store that have some great search rankings, but those products are unfortunately being discontinued. While new products will be arriving, it will be necessary for them to have different SEO URL's than the old products. That's the problem I set out to solve - we can now manage redirects (which provide a 301 HTTP Status Code, and therefore preserve a lot of your previously won "link juice") through a very simple interface.

It's only works with Opencart 2.2, but it is free to the community, and I would welcome feedback.
It's available for download in the Opencart Marketplace. I'm already hard at work rewriting it to work with Opencart 2.3 (and be a lot more polished off than this one), but I figured why let the old code get forgotten about.
So, if you're curious, please check it out and let me know what you think. Thanks!