The biggest plus is that Kidd has brought the leadership intangibles this team has needed. Harris may continue for many years to be an effective scoring guard who handles the ball, but we must recognize that he - while sometimes electric and a very fine player - was a long ways away from becoming a floor general. Those PER stats that so many touted to dis this trade can measure a player's offensive impact, but what has this Mavs team needed most, one more scorer, or a leader? Kidd's that leader, and we feel that's the biggest reason why his impact has been and will continue to be transcendent on this Mavs group.
Second, while we acknowledge that Kidd is older, in the next few years can we say with any certainty that Harris will play more games? No. In the last few seasons, it is the older Kidd rather than the younger Harris who has been more reliable. And in our estimation, now that the Mavs have him, aren't they likely to keep Kidd for multiple years rather than one or two? If the Mavs can end up with 4 or 5 years of this sort of play from Kidd, then no matter what Harris does, it will be seen as a great trade for Dallas. And we like the odds on that outcome.
Third, while Harris may be the more effective scorer, Kidd is an impact player who changes the whole dynamic of the game. His ability to see and make passes to players away from the ball makes the defense defend all five players, not just the one or two closest to the ball. With Kidd the Mavs gained something they've wanted for several years: the ability to score in the paint, given his ability to find the open man near the basket.
How about losing pieces like Diop and the draft picks? We hated to see Diop go, but we have to admit that in Avery's pecking order, he wasn't going to be a factor anyhow. The same applies to the picks: hate to lose them. But to go from Harris to Kidd, from a scorer to an impact player who can provide leadership, it was worth it.