so not really a fleshed-out idea, but kind of
I'm amazed how relatively "unintelligent" word processing software has remained over the years
I dream of a program that has some serious (and feasible) tools and features that would actually be useful to a professional writer
examples:
1) a clean, collapsible space accessible below any given sentence for working on sentence variants, which can be sketched here using spoiler tags:
[Candidate final sentence] "{subject} {verb} {adjective} {object}"
2) a robust 'semantic field' exploration tool: you click on a verb, noun, adjective, or adverb, and a menu / box pops up that lets you efficiently search for synonyms, related terms, definitions, antonyms, etc.
3) some kind of sentence diagramming functionality if you want to really map out how your prose is flowing and what patterns are there
4) just a more flexible and simpler way of grabbing and moving words, phrases, and sentences into different places, with the rest of the text expanding and contracting around these adjustments
5) advanced word searching and reports: are we overusing a particular verb or noun or whatever? can we get a look at frequency and patterns of typical sentence lengths in our text? what about the same for word types (syllable count, vocabulary level, Latinate-versus-Germanic)?
6) inclusion of style guidelines (like the CMS) for questions regarding punctuation use, quotations, parentheses, dashes, citations, dialogue formatting, and so on
7) advanced grammatical assistance: show me all the possible modifier slots in a given sentence; highlight all the verbs in this passage so I can focus on them; same for adverbs and adjectives; etc.
8) bonus magical fairytale wish: include a 'figurative language dreamatorium' module, where users enter a separate area with tools and resources and models and examples available to help them craft decent similes and metaphors and whatnot
okay, now make it happen, internet!