Aye, although I have a feeling that Leeds might stay up this year you know. Not sure who'll come down though.
I think the gap is big and getting bigger (the five subs rule is a game changer as well), but there were some particularly unsuited clubs in recent years. Luton obviously, Sheff U with no money, Burnley with a team that in the champ was made up of loans they lost, Southampton with a style of play that was insane for this level, Ipswich with a double promotion and the same squad from league one etc.