As for Slack, I don't really consider that documentation. It's not really usable in the same way. It's more akin to IRC. It's potentially very helpful, even when the documentation isn't helping, but it's not the same thing. Maybe I'm just old, even though I'm not that old... I think...
Anyway, I hope this doesn't come off too negatively overall. I really like the idea of Talon and I'm comforted by it's existence, in case my hands start acting up again. From my attempts to investigate it I got a few glimpses into just how deep you've gone, even down into the speech model itself, to make it what it is. And I know any interface to something as complex as this is itself a large series of extremely ambiguous trade-offs that's just painful to make. And of course documentation itself takes time to create, and then needs to be kept up to date, and all that. I get it.
If it didn't seem to hold much promise, I wouldn't be so sour about failing to figure out how to use it effectively.
One thing that might be worth considering is moving to a source-available model, if full on Open Source doesn't suit your goals. Having the option to try to figure things out by looking at the code could be very helpful.