Fully agree that they should get back to their roots and start being actually pro-working class on economical matter. Alas, the establishment is too afraid of alienating their wealthy donor class to appeal to the "poor". Maybe after a democratic tea party?
But I don't believe that they need to be "centrists" on identity. What even is centrism anymore? This country has shifted so far right recently. I think the issue is that their "rainbow capitalism social justice" sounds hollow (because it is) if they don't consider economical class as an important matter. Start there and you can keep fighting against -phobias and -isms, just don't make them the center-piece of your messaging.
Centrism on identity would be a more modern version of don't-ask-don't-tell. When Republicans try and nail Democrats into corners about LGBTQIA+ issues... respectfully refuse to engage:
'I think all Americans that pay their taxes and contribute to our country deserve life, liberty, and the pursuit of happiness.'
Focus on multiculturalism and personal automomy as a star-spangled, patriotic American characteristic.
GOP: 'So you want to give trans people healthcare?'
Democrats: 'We want to give Americans healthcare. Why do you want to take it away from any citizen?'
Start throwing more punches, instead of being surprised every goddamn time the other side does.
There are fewer identity voters than there are economic voters.
They'd win more elections if they trended centrist on identity and progressive on the economy.
As has been quipped after they lost the last election, "poor" is its own identity.