Lee is, like Corey Maggette, a problematic player.
First off, his defense is nonexistent so he’s a one side of the court player. And while he puts up decent numbers, he’s never been a dominant force. Comparing him to Amar’e is unrealistic because people have gameplanned for Amar’e; not many teams went to NY these past few years thinking, “Man, we’ve got to do something to slow down David Lee!” Realistically, Lee would be a third option on a winning team however if he’s the 3rd option, he needs to focus more on improving his defense or else he’s going to probably end up on the bench during crunch time, when most good teams can’t afford to play a guy who can’t play both ends of the floor.
Lee’s problems have nothing to do with Warriors luck, it has to do with the Warriors once again investing too much money in a player that can put up good numbers on bad teams but not actually produce the wins that Berri likes to pretend he does.

On what basis would you suggest that he’s improved?

Well, I consider the facts that he’s playing a totally different role on a new team with an inexperienced coach. I also consider the fact that Wilson Chandler bit half of Lee’s left elbow, and that fiasco clearly hindered his play.

As some have said later in this thread, Lee is best used as a small center in a pick and roll offense. It is not to Lee’s detriment that he is in some bizarre “motion” offense where the guards often dribble for 20 seconds. If I were coach, I would run pick and roll almost exclusively with Lee, and I would never try to isolate him in the post against superior defenders (like Smart tried against Boston and Atlanta).

I have said this in other threads but it’s relevant here: for whatever reason, Lee and Biedrins just don’t complement each other very well. We could get into the details, but it probably doesn’t really matter. So strategically, I think the Warriors should start an “offensive” unit and come off the bench with a “defensive” unit.

To start the game….Curry/Ellis/Wright/Vlad/Lee. I would go run and gun offense (Nellie-style), especially at home against road-weary opponents. When Curry picks up his usual two fouls, you must come in with Reggie. (Keith Smart foolishly comes in with Law). If Vlad stinks, then I would bring in Lou. When I substitute big men, I would pull BOTH Vlad/Lou and Lee at the same time and insert BOTH Udoh and Biedrins. This lineup, which would look more like Ellis/Reggie/Wright/Udoh/Biedrins, goes for steals on the perimeter, yet still has size, rebounding, and shot-blocking. Points from this lineup should come off defensive rebounds and steals.

So, while this is my particular view of this team, I don’t see how I could possibly blame David Lee for any of this. I thought the sign-and-trade was a bad idea (look it up), one of the main reasons being it was clear Lee’s stats were inflated. I didn’t think he was that good last year, and I don’t think he’s that bad this year. He’s still David Lee, just a year older and wiser.

Interestingly on defense, DLee allows
PF- .497 efg%
C- .507 eFfg%

and for the sake of it:
Monta
defensively
v. PGs .443 eFG%
v. SG- .551 eg%

I see the PF-Center thing, discussed by Tafk, as a fluke. The simple truth is that, regardless of his offensive position, Lee’s offensive game is basically the same. There’s no reason why we can’t run pick-and-rolls when he’s the "center" – but the simple truth is that we’re not doing it.

How is it a fluke. It’s a fact. PnR v. a PF, he still has to content with a weakside center contesting a shot (ESPECIALLY when the center can cheat off andris).

When Vlad’s in spreading court, key is more open, easier to finish.

Lee isn’t blake griffin or Amare. Or even Bosh/Pau who aren’t explosive to the hole but their length is hard to guard.

Physical attributes matter in these situations. To maximize Lee’s PnR ability we can’t have a center at the rim altering his shots.

This speaks to your point more 3-9 footers. He’s stopping short cause he can’t go inside.

And his numbers in the two seasons before D’Antoni were as good as his D’Antoni years. Also, according to 82 games he has played as many minutes at C as PF this season (although that hasn’t been updated since Jan. 19, and Udoh seems to be taking the lion’s share of the non-Beidrins center minutes, since then).

I don’t think his inferior Warrior performance can be attributed to his position.