If a Gore 2020 platform contains both single-payer healthcare and the abolishment of the electoral college (in addition to his trademark environmentalism), the Dems may have a chance at unity.
He's also probably the only candidate who could make "Hindsight is 2020" his slogan and make it work.
He shouldn't make such a personalized slogan. Reminds me too much of "I'm With Her". Something like "A Return to Decency" would be better. The Democratic ticket of 2020 needs their equivalent of MAGA - something vague, universal, and empowering.
I don't think we should be recycling 100 year old Republican campaign slogans.