The Democratic party should not be looking for the next Obama. They should be looking for an authentic candidate that fits the voter's values the best without pandering to corporations. The new candidate should also be in touch with the younger community, which is where the party's strength lies, and should NOT alienate whole swaths of the United States.
Another Obama is not needed. What is needed, is another good candidate who is connected with the people.
Her name is AOC.
AOC is wayyyy too polarizing to be the next Obama. She has hardly any appeal outside of major cities and young people. I like a lot of what she fights for, but her messaging can be godawful at times. She is good at garnering media coverage, but she's just too hated and extreme
That assumes the electorate and the American political landscape will be identical in 20 years.
Definately, there optimal canidate depends upon the time. Obama was the right fit for the moment, and the right person for the moment in the future is unknowable because we don't know what the future will bring.