Much like the consensus here, I think Walsh had a subpar tenure here in New York. I won't rehash the same points made by guys, just preface my criticism with the fact that many of his moves were made to appease D'Antoni and his flawed system. Walsh was more a traditionalist and was trying to acquire personnel that fit a "revolutionary" system, which caused him to have a higher strikeout rate than norm. Still, Donnie hired D'Antoni so he doesn't get a pass in my book.
To expand upon what was said, the moves Walsh DIDN'T make had almost as bad an impact as the moves he did make. That list includes:
1.) Not trading Jared Jefferies AND Nate Robinson to the Kings during the 2008-2009 season for cap space. Robinson accounted for 3 win shares, which resulted in us having fewer pong balls in the lottery and a lower pick than the Warriors in the 2009 draft. Why is this important? That pick resulted in Stephen Curry who might be almost as good as Melo is. If we had Curry during the 2010 offseason, LeBron might've been more willing to become a Knick. That move turned out to be a double whammy because we ended up giving away Jordan Hill and future draft picks for Tracy McGrady to move Jefferies contract during the 2009-2010, which set this team back for years.
2.) Not trading Eddy Curry to the Pistons for Chauncey Billups during the 2008 offseason. I wouldn't have done it at the time but I didn't have the information that Walsh should've. Billups turned out to be the more valuable player over the subsequent seasons, which would've come with extra incentives like draft picks to compensate for Curry's youth. More importantly, we could've just as easily moved him later in the season for Allen Iverson and been sitting pretty with 2010 cap space AND PICKS, (maybe even Marcus Camby since the Nuggets gave him away for nothing).
3.) Not trading David Lee sooner. During the 2008 draft, it was rumored that the 5th pick (Kevin Love) was in play for Lee's services. It was a gamble at the time but trading him to the Warriors 2 seasons later for a lower probability of equal return was tough to swallow; we just gave him away for nothing. Had we moved Lee for that pick, we would've had two draft picks in the 2008 draft, which brings me to the next point.....
4.) Not drafting Brook Lopez or Eric Gordon. Both were superior players to Gallo then and this remain the case now. These two, along with Stephen Curry could've brought the MIA big 3 to New York since they form a better supporting cast than what they currently have and at a fraction of the cost (in 2010), which would've left more flexibility for us to pursue players.
5.) Not forcing the Clippers hand during the Zach Randolph trade to tender a pick swap in the 2009 draft. We gave away a 25 year old, 20-10 big man for nothing more than cap space and a dude with a bad heart (Cuttino Mobley). Adding the pick swap, would've seemed benign because the Clippers were in a "win now" mode and we were evidently rebuilding, which gave the impression of us being a worse team. The Clippers got the no.1 pick in that draft, Mr. Blake "I've been better than Amare since I came into the league" Griffin.
6.) Not trading Al Harrington to the Bulls for the Bobcats first round pick. The Bulls were reportedly interested in a swap after they dealt Tyrus Thomas to the Bobcats for that pick during the 2009-2010 season. Instead, we elected on keeping Al Harrington glued to the bench for the 2nd half of the season. Good move D'Antoni/Walsh!
6.) Not keeping Corey Brewer. Brewer is not a remarkable player but had we kept him until the end of the season, we would've had enough contracts to sign and trade for Chandler outright; not using our amnesty on Billups in the process. This team would be in such excellent position moving forward had we had that thing to use on Amare Stoudemire.