My hope is that, with control of all 3 houses, the Dems will institute voter protections and other reforms to prevent the kind of clusterfuck we're seeing now, along with other changes to correct the problems 45's corruption has exposed. Immigration reform, reconfiguration of our financial system, a new philosophy to guide criminal justice, public-option healthcare--much is possible when everything is in flux.
What I'd really love to see politically is for the Democratic Party to split. If the progressive wing were to become a separate party--the new far left--the classic Democratic moderates would be the new middle, which is where most people are more comfortable. The Democrats and the Progressives could govern by coalition, while the true conservatives could escape the Trumpists and Tea-baggers by joining the moderate Dems or forming their own 4th party. Parliamentary government can be raucous, but I think it would be far less dangerous than the current polarization.