YMMV, but after following the 2018 elections closely, O'Rourke seems like the only candidate in that batch with a strong personal appeal. There were others who ran out of a unique political niche (Sinema) or who ran particularly strong campaigns (Abrams), but Texas was the only contest where it seemed like no other candidate could have done so well.
Eh. I don't think any Republican other than Rick Scott was going to knock off Bill Nelson that year. It took Scott's own goodwill from his hurricane management in 2017 to really put him over the edge.
IMO it's hard to compare the statewide maps in Florida and come away thinking that the candidates had that much to do with the outcomes in 2018.
Of course in a razor's-edge contest it's inarguable that they mattered.
I still wonder whether that Senate loss had more to do with Scott's Guns-of-Navarone-level campaign spending, or with Bill Nelson being vulnerable to a "doddering old man" caricature that would have been effective regardless of his opponent.
This question deserves some national attention given the age of the leading Democratic presidential contenders.
Well Trump isn't that much younger than Bernie or Biden. But I think it'll be hard to paint either as a "tired old man" like Nelson. Nelson didn't even really start fundraising/campaigning until September 2018 because he assumed that Scott would be another pushover like Harris or Mack. Both Bernie and Biden have a lot more energy, and won't take anything for granted. They should be fine on that front as long as they don't collapse in public a la Hillary at the 9/11 memorial.
And I do think Scott was the only one who could have beaten Nelson. As a popular incumbent governor who also happens to be a multimillionaire, Scott was just about the strongest candidate Republicans could have fielded for that race, and considering how close it was even with him, I find it hard to believe that anyone else could have won.