Here is how I'd defend the Lakers, especially in this format:
1) I wouldn't waste my time debating whether or not Shawn Marion was an elite defender in his younger years. Better basketball minds than mine have waxed philosophical on the topic enough times in the past so that its kind of a given. It is also kind of an irrelevant point involving one role player that doesn't concern the Lakers.
2) The Lakers' biggest offensive critique is that they lack strong 3pt shooting from the guys who are going to play the most minutes (Worthy, Garnett, Payton), while the strong 3pt shooters only have one guy (Dumars) who is going to really see significant minutes on the court.
The way I'd defend that is first mentioning that while only one of the starters is a strong 3pt shooter, none of the starters are lane cloggers. Kareem, KG, Worthy, all those guys could hit a mid-range shot, and because of that danger, they'll be no more a liability in the middle than KG is now on the Boston Celtics, and since Payton is a much more versatile offensive player than the current incarnation of Rondo, he ought to be able to move around a lot more.
I'd also mention regarding James Worthy that he never played with a rotation that involved heavy minutes for bombers from outside, excepting one current coach and former player. Magic Johnson was never a strong 3pt shooter during his prime, and he still managed to get 4 rings during what many people would refer to as the most competitive era in basketball (although I think they'd be selling the post 2007 era pretty short) with James Worthy as one of his primary running mates.