he made it an awful lot easier for the speculators and irresponsible borrowers
He was not a Banker; He was a Central Banker. He can't provide adult supervision to stupid lenders/bankers. His mission is to keep the FFR as low as possible and money supply sufficient without causing undue inflation and promote near full employment. On those grounds he was excellent. Considering the challenges in his tenure, he performed brilliantly.
Folks, the US economy has been taking water continuously from 1970s onwards. He engineered the ship without sinking it for 20 years! To understand his genius, mark my words – this ship is definitely going to sink in the next 20 years. May be, once underwater and drowning, people will understand what a heroic job he did.