that Darius is not doing himself any favors out there on the court. Blame Kobe's ball-hogging all you like, but that's not the problem with Darius. The problem with Darius is that he tries to do too much with the ball. His play is best described as being "aggressively out of control" at times. There are moments when he runs the offense efficiently, and takes decent shots, but IMO they have been few and far between. And he's a bit of a liability on the defensive end, but that's been covered up by the fact that the Lakers as a whole are an awful defensive team.
He's far too inconsistent on both ends of the floor at this stage of the game, when some stability is seriously needed at the point guard position; hence, Duhon's starting and other possessions where Kobe is the guy bringing the ball up court. It also helps, of course, that Duhon is familiar with D'Antoni's offensive system and can direct guys to their proper positions in the set.
Darius seems to be willing to learn and improve as a player (he has praised Kobe and others on the team for being great teachers), and he apparently gets high marks from teammates for that reason, but the reality is that it's tough to learn on the fly while playing for a franchise with astronomically high expectations of not just winning, but winning RIGHT NOW.
I think it's only a matter of time before he's traded. I don't think that he should be, since he gives the Lakers some athleticism that they are sorely lacking. The only way it's justified is if the Lakers get some better athleticism/shooting/decent defense in return.