On paper, Season 30 ('04-'05) doesn't seem like it's be competing with Seasons 6 and 11 for Worst of All Time.
Cast on paper seems good if not great
Fred Armisen
Rachel Dratch
Tina Fey
Will Forte
Darrell Hammond
Seth Meyers
Chris Parnell
Amy Poehler
Maya Rudolph
Horatio Sanz
Featured players;
Finesse Mitchell
Rob Riggle
Jason Sudeikis (first episode: May 7, 2005)
Kenan Thompson
Only problem is everyone was either past their prime on the show (Fey, Horatio, Darrell), still hadn't found their voice on their show (Kenan, Seth Myers), would never find their voices on the show (Finesse and Rob Riggle), or were just having their worst tics encouraged (Maya and Amy Poehler). Only two people in their prime were Forte and Fred Armisen and you can't build a show around weirdos who are usually in post Weekend Update spots.
Combine that with a horrible selection of hosts and you got a real shitshow.