My perfect solo roleplaying tool would...

1. Effortlessly generate content for ALL game master responses.
2. Generate content that requires little to no interpretation.
3. Generate content that is easy to interpret (if interpretation is needed at all).
4. Generate content that has as few alternate interpretations as possible (if interpretation is needed at all). My ideal number of possible interpretations for generated content is ONE, by the way.*
5. Generate content that fits the context (or at least easily leads to an interpretation that fits).

The concordance generator I whipped up does #1 perfectly. It also approaches the rest of my wishlist more than any other tool I’ve tried or checked out (except for dungeon generators in the narrow context of a dungeon crawl), but there are some downsides:

1.  Sometimes content is sparse and does not fit context. This either requires more lateral thinking when interpreting or it may require re-generating the response using a different keyword, which I consider bad. 
2. When I get content that fits the context, I will often have to “curate” or search the responses for the first piece of content that works as the satisfying GM response. It's not perfect, but I find it much less jarring than having multiple ways to interpret something and then being forced to choose between them.

Just writing this down is giving me some ideas for possible enhancements. 

*#WritingWithDice tries to do something by attempting to narrow your possible GM responses by imposing limits to your brainstorming.