Currently we don’t plan to modify the way how our plugin works. As you said it’s already possible with our plugin via Redirection Rules tab but on the other hand we already have decent community of users that are used to the way our plugin (let’s say, new plugin out there) works currently.
We could support both but it was never requested by anyone else and it sound like something that is not necessary required or needed.
If you have a lot of URLs you can always make JSON file (based on exported example of single or two redirection from our plugin) and fill it with your redirections, then in bulk import them to the plugin.
As far as I see, our plugin is much more advanced in terms of features and I hope you will understand that we don’t want to touch things that already work as designed without issues.
Let me know if you will need any further help 🙂