I agree with a lot of what Marv said but I also agree with JM that we shouldn't credit or blame previous managers for current managers' performance, I'm not sure where this has become so prevalent but I suspect it is partly to try and protect Mogga's legacy a little. He was a great player for us, no doubt, no great shakes as manager frankly. Southgate was a great player for us and a terrible manager, that wasn't McClaren's fault and however well he does with England now is irrelevant.
Karanka did well, no one expected promotion from him as such and he achieved that, it was nothing to do with Tony Mowbray who had been gone nearly 3 years by the time it happened.
Monk did pretty poor, it was nothing to do with the squad he inherited as he had a load of money to spend and underperformed against those expectations. It wasn't Karanka or Agnew's fault that he couldn't keep us at least in the top 6.
Pulis did ok but not well enough. No one before him shoulders the blame for that, we should have been in the play-offs at least (as were the year before) and probably expect to win them.
Woodgate did terribly. Yes there was no money left but consensus view on here was that mid-table would be ok, as long as we didn't flirt with relegation. He'd inherited a team that finished 7th, lost a few and had little money to spend, but mid-table/top 16 would have been fine in his first season. He almost took us down. Far too big a fall and Pulis takes no blame for that.
Warnock has to get us top 10 to be considered a 'success' I'd say, top 6 would be fantastic. I won't be making excuses about Woodgate for him if he fails to do that. But I've no doubt that he will achieve it. At absolute worst we'll be in mid-table, where Woodgate should have had us.