He's been relegated with West Ham, Southampton (twice?), Portsmouth, and now QPR.
His financial mismanagement bankrupted Portsmouth and now the club are on the verge of ceasing to exist. He left Southampton in such a sh*t state they dropped to league 1 and now he's spent how much at QPR, and they still got relegated without a fight.
Two top four finishes with Spurs (how much did he spend there by the way?) do not, a good manager, make.
Redknapp wasn't relegated with West Ham. The lowest he finished was 15th in 2001, and the highest was 5th in 1999. I don't know enough about football finances in the 90s to say how good or bad a job he did, but his record of bringing through youth players who went on to be sold for huge money was quite impressive (Ferdinand, Carrick, Lampard, Joe Cole and Defoe).
He didn't do well at all with Southampton, but he did take over in December with them bottom with one win and they didn't go down until the last day. He was gone by the following December and ended up returning to Portsmouth and keeping them up, before winning the FA Cup and getting the Spurs job in 2008. I'm not sure why he gets so much blame for the fact that the Russian who bought Portsmouth turned out to be a fraud, or why you think he took them down.
Also, I think QPR would have been all right if they'd hired him in the summer instead of letting Hughes go on that bizarre spending spree.
I don't particularly want Redknapp, but he isn't nearly as bad as people like to make out.