Ernie got off to a pretty good start, but his drafting has been pretty bad and his trades were worse. He probably didn't much choice, but to give Arenas a Max deal, but giving Gil a 100 million dollar deal when he had that type of injury and hadn't recovered from it and apparently never did... he never regained his speed or explosiveness was a bad decision. The free agents he brought in to compliment the big three were not good choices.
I think it's fair to tip our hats to the Ernies for giving Wiz fans a brighter spot in their history, but in the end, Grunfiel failed for many of the same reasons that Cerrato did. Poor drafting. Poor free agent aquisitions and terrible trades.