“Why do all these reports omit Sen. Bill Nelson (D-FL)?”
Nelson was beatable in 2012. However the establishment decided to run a legacy, Connie Mach IV, instead of a strong candidate.
It might have been OK if it was his father but CM.IV was indeed a light-weight and helium-inflated at that. Of course it was 2012 so the entire GOP thought that all we had to do was run Romney and Obama was toast! We forgot that Obama had a free 3 months to smear Romney along with the MSM 'unbiased' coverage so everyone got stonkered! The Good Lord knows that FlGOP had better candidates but what is past is past! We will need better in 2018, Nelson looks healthy enough to run again.