1) Kidd is still a better player than Harris. Harris would demolish Kidd in a game of 1 on 1, but that does make him the better NBA player.
2) Swapping them straight up does not make Dallas better right now.
3) Dirk is playing the best ball of his career alongside Kidd instead of Harris. Anybody who has watched him since the beginning of the 08-09 season would easily concede he's even better now than he was from 2005-07.
4) I'd rather have 80 games a year of Kidd than 55 games a year of Harris.
5) The two first-rounders are in the mid to late twenties because Dallas wins 50+ games every year. For $3 million, Dallas can buy a late first-rounder with Cuban's deep pockets.
6) It's true Devin Harris will still be in the NBA in 2014 when Kidd is beating his next wife, but the Mavs made the trade to get better now, and it worked. Harris is not some transcendent player that Dallas will regret giving up. It's not Vlade Divac for Kobe Bryant's draft rights.
I find it hilarious that this is getting mentioned as one of the worst, if not the worst, trades of all time, when it's clear that both teams met their goals: Dallas got better in interim, Jersey salvaged a nice player considering Kidd wouldn't have resigned there. Joe Johnson for Tony Delk and Rodney Rogers was worse.