What exactly would Dems have to change their thinking to? They managed to win, despite being the only partly being held accountable for failures/falseties, despite voter suppression and other shenanigans, despite a system stacked against them and despite a massive propaganda machine having a stranglehold over a lot of voters. For some reason, it is constantly understated but this was quite an achievement, imho.
They seem poised to try and get rid of at least some disadvantages, but they will have problems doing that while still adhering to the rules, being more scrutinized by their own voters than Reps ever were and not having as much power as the latter had. I don't know what thinking they could assume to change any of that. Become more like Republicans? Screw the rules, screw ethics, try and make a cult of personality of their own? Go all in on progressiveness and hand over a batch of voters to the Republicans? Idk, I just don't see the thinking the Dems could change to without becoming just as bad as the Reps to do better.