Nash hasn't mattered. He's not what he used to be.
Dwight Howard has actually been a monster. He's been really good when he's playing healthy, better than Bynum would have been, but overall, the trade has been a complete bust for all sides involved. I don't blame Dwight at all; he's played well when given the chance.
Kobe is Kobe. He's one of the best players in the history of the league and he's also the player that has missed more shots than anyone else in NBA history. When he passes the ball, he's incredible, and I honestly think that he could have been even better if he'd played that way throughout his career, and if he had tried to be, he could have been one of the best point guards in the history of the league (obviously he's one of the best SGs in the history of the league too, but he still takes too many shots that aren't there). Case in point, when he stopped shooting every time he got the ball, the team really improved, and with that the morale went up and the chemistry went up. Despite the recent downturn, I think the Lakers are a threat if they pull off the 8-seed against the Spurs, but I don't think they can beat the Thunder, Clippers, or Grizzlies, even without Rudy Gay.
The worst thing this year has been Gasol. He's been a sad slouch and is no longer even in partial control of his spot on the team, and that's saying something when you consider that he was the star forward of the division a few years back, fighting some guy named Chris Kaman. Now he's a long, long way behind Blake Griffin, who by the way is Dominique Wilkins' long lost cousin or something. Maybe he's just in costume.
D'Antoni has been okay, not great, but not bad. I think it's mostly that the two holes this year are underneath when Dwight is hurt and Gasol continues to suck and some shooting capability on the outside, but that's better since Earl Clark has started shooting relatively consistently and Kobe passes.
The Lakers will be fine if they make the postseason against the Spurs, maybe put up a fight. They'll be fine this offseason and next year for sure. Hopefully Kobe has a few years left; he's fun to watch.