I read a fair amount of Pynchon, but neither GR or the others jump out as having a "positive impact" on me. It's been too long, and I guess I'm not really clear on what that means. With some books I walk away with positive affirmations or a sense of better understanding. I suppose there was some of the latter, but not the same sort of catharsis. The world is dark and disgusting and confusing. I'd be lying if I said it didn't impact me though, which I'll grant, probably for the better.
I find Gravity's Rainbow to be, in it's ugly way, somehow life affirming. It's also very funny at times, which is always helpful, and very long which might help people right now.
Right now I think maybe people will appreciate being in a zone where the normal rules have ceased to apply (Allied occupied Europe in the novel), and where there is a lot of wrangling about who the winners and losers in the new world will be.