As happy as I am to see Twitter potentially go on many levels, I think in the short term at least the effect on both political/corporate activism and media criticism will be negative. Things like the Ukrainian resistance, the Arab Spring, BLM, #MeToo, etc. could never have reached so many nationwide or worldwide and demanded notice and action from the powerful, or connected to parts of the world that might have had no real idea, without the platform of Twitter. Activists, freedom fighters, could not so easily have communicated or reached a wider audience. China and Russia, American law enforcement or corporate media in America, would not face the constant pressures they do, and Trump, etc. here would not be facing such strong headwinds against them today.
I would love to keep the good and leave the toxic, but that's not how human nature works; you always get both. I can only hope that what comes next will still find an easy way for people to connect and challenge injustice.