Hi Sladyn,
Thanks for sharing it! I sent some comments in the Google document. Overall it looks very promising, but right now there are many inconsistencies between planned deliverables, planned scopes of changes and the implementation plan. My suggestion would be to spend some time proofreading the doc so that you can ensure that all sections are aligned.
I am also not sure about putting the ChatOps into the scope, because it has nothing to do with the Checks API (at least in a way it is documented now). It is indeed a useful feature with high community value, but it may deserve a separate project. I definitely would not recommend to commit on delivering it, but it might be something to consider once the main deliverables are implemented
Best regards,
Oleg Nenashev