It's a good move. They don't have much to lose and Graves is not as bad as everyone is making him out to be. While I don't think he will be a good option in close games, there is a chance that he puts it together.
I never thought Looper was in danger of losing his job. I guess the fantasy geeks have been throwing the idea around even before the season but Looper has been pretty effective and I can't imagine why the Mets would be actively seeking to replace him. They have other problems that need to be addressed like 1B and 2B.
"Think of how stupid the average person is, and realize half of them are stupider than that." ~George Carlin