As it has been said a lot: you can use vim or whatever editor to do this just as easily for the amount of time this would save you.

How many times per day are you actually rebasing interactively? I myself might do it once per week and that in a project with 6 developers with a fairly strict commmit policy. I can only imagine having a job where doing interactive rebases is the only thing you do before you get a return of investment on a. building the tool (you) and b. learning how to use it (others).

You could probably have learned to use vim in the time it took you to build this, at least the basics. You could also start learning about vim by enabling vim-mode in your editor. Most editors have one at least.