I don't expect him to say anything. Don't get me wrong the problem isn't so much Bernie himself as it is progressives' worship of Bernie as the new messiah of progressivism, though he's not doing nearly enough to dispel that illusion. Now what I want him or any other progressive leader with national recognition to say is that the only hope for change will come from the streets and that the people must protest, march, strike, boycott and whatever else they can do until their demands are met. Again I'm not expecting Bernie to say this, but a time where America needs geese Americans must be willing to call a duck a duck and accept that no matter how much they squint a duck will never be a goose. This is necessary before you can search for the geese you need.

I think it'll be most powerful during the primary campaign when they've put in the work leading up to it

At the rate America is going primaries won't matter because elections won't matter. If you think Trump won't have significantly curtailed democracy in America by the midterms you need to take a look at the news for once. The most important obstacles to taking down the oligarchy are Trump's wannabe authoritarian regime and the entrenched political establishment, and Bernie's tour is doing nothing to address the former and very little to address the latter in a reasonable timescale.