My thoughts? Obama is, as you note, too much of a spotlight hog to be effective for the Democratic Party. He literally sucks all the oxygen out of the room and either deliberately or inadvertently upstages everyone around him. Frankly, he doesn't give a shit or know about hyping up others and being supportive or endorsing to garner downballot success. The dude wants to be rich and hang with celebrities on yachts and shit. Which is just as well, because he's incapable of doing anything constructive at this time - even if the Dems convince him to go out and try to rally support he's either going to make it all about himself or remind people of the bitter failures of his administration to deliver on big promises. The shine is off and his message is sour.
Clinton's entire powerbase was built on the expectation that she could deliver her husband in the 90's, and eventually herself as SOS and President. That all collapsed when she lost in 2016, with a massive debt of favors and money that was going to be handled once she had the White House. We saw how after the election her 'foundation' immediately shriveled up and died, and she vanished. Everything had been suborned to support her run and eventually victory, but that was stillborn. You can't do anything with those structures even if you tried to convert them, they still have liens on them.
Its all fallen back on the general Dem superstructure, Pelosi and the others are in charge for the simple reason that
they are the only survivors. The Clintons smothered most of the back bench to prevent another dark horse from bucking Hillary's ascendance, the Dem civil wars and fractionalism have taken out protégés and successors with too-violent competition and sneaky tactics. Old Hagosi and Jewmer are the only ones left that still have access to the various levers of power, the knowledge of the entire complicated machine interlinking Congress, the media, law, NGOs, etc. Their grip is old and weak, constantly slipping as things spiral out of control due to outside forces and the 'new kids' fighting for the control yokes because its they're turn now' and they don't give a fuck if they can't reach the metaphorical pedals or see in the mirrors. These overt overtures to Soros are super-desperate, they would normally never ask for his favor openly, but confidence in the Dem's ability to deliver is rock bottom and they need unholy amounts of money to try and staunch their bleeding.
What the fuck do I know, though? I'm just some asshole in an alley with a knife, ask
@Gehenna for actual analysis.