You’ve literally just revised your opinion of him. I feel it is confirmation bias as you have never liked Starmer & still hold a candle for JCWho's revising what?
I voted for Corbyn in 2015 because, like Yvette Cooper and Liz Kendall, Burnham ran an uninspiring campaign. He wised up towards the end and started to offer a more left-wing vision, but by then it was too late. I respect him for his stance on Hillsborough which was opposed by Blair (in Murdoch's pocket, as usual).
As for now, I'd settle for Burnham, as would many a soft(ish) lefty, I think. Anything has to be better than the present catstrophe and the all out factional purge the right of the party has now started.
I would welcome JC being a policy adviser btw, not absolute power but he has come up with some good ideas.