I was never a big fan, but unfortunately I'm also quite cynical. I have a bad feeling that his replacement will make me long for the good old days of Dan DiDio.
To me his legacy will be bringing back Barry Allen unnecessarily, more or less neutering the impact of the Crisis on Infinite Earths. Also in his legacy would be the New 52 fiasco, and turning the majority of DC's heroes into snarling jerks (but the latter might not be entirely his fault).
The one good thing he did (IMO) was giving the go-ahead to bring back Hal Jordan, even though I think Geoff Johns' run should have ended with Hal dying/being permanently retired, thus giving the character a truly great send-off instead of what they did to him in the 90s. I liked Kyle Rayner but Hal and the Guardians had to come back if only to erase the mess that was made of them in 1994.