1) A word processor provides spellcheck, grammar check, and some text enrichment aka style checking. My software provides spellcheck, minor grammar things, and very heavy text enrichment. Desktop software comparable to my text enrichment technology retails for $130. My spellchecker also detects homophones (where, were, etc.) which the Firefox spellchecker and the Wordpress spellchecker do not do.
END USER BENEFIT: checks you don't get in a word processor, improvement over the default spellcheck.
2) c+p from a word processor back into Wordpress is cumbersome. Claiming that all people follow this practice is misguided. I agree some people do this and others use standalone blog editors. However I see CMSs bringing in more and more word processor functionality as time goes on. After all, you are editing and producing content in the CMS, these tools should should be available.
END USER BENEFIT: convenience, safety net built into the CMS for those times when writers are too lazy to open a word processor
3) my engine makes it easy to add rules to enforce organizational style guidelines in writing. Imagine you have a corporate blog where many employees are producing content that the public sees. Most organizations worth their salt have a style guide. My software makes it easy to enforce style guidelines. I don't have a rule editor in place for everyone yet but my engine can support this.
END USER BENEFIT: centralized control of style guidelines, ability to enforce style guidelines
Think beyond Wordpress. Any web app with TinyMCE can use my service to embed language checking capabilities as shown in that screenshot.
(note--even though I'm building writing tools, its 6am, I've been up all night, please forgive my sloppy writing style right now)
I like how you've realized the challenge of "education your market," very strong words there, and it sounds like you have some plan put together.
I think 2) is the greatest draw, the convenience factor.
Best of luck.
