re: Most talented SEC team to lose 4 or more games?

1988 Florida had a ton of good players - Emmitt Smith running behind a great O-line and a stout defense led by Trace Armstrong, David Williams and Louis Oliver (all of whom were All-Americans and first round draft picks).

They started out hot (5-0 and highly ranked), then lost to Memphis State at home and got routed by an absolutely anemic Vandy team at Dudley field. It was all downhill from there, with Daddy Bowden delivering the death blow in a blowout as all eyes turned to Duke where legendary alum Spurrier was guiding the Blue Devils to a surprising ACC championship.

ETA - Johnny Majors also had a very talented Tennessee team in 1988 that started 0-6.