What do you want to invent?
I was the inventing sort, which I most certainly am not! I've long wanted to create a program that would scan text for repeated words. (With an exclusion list of common words like 'a,' 'the,' 's/he,' 'it,' 'then,' etc.) It is such an aggravation whilst writing and editing my stories and novels to replace one word in one place and find (much later) I'd used it already in an adjacent paragraph. Especially in action scenes; those give me so much editing trouble.
So it wouldn't do my editing for me, but at least it would point out things my blind eyes are missing!