Any concerns about using Move as an aiming device should be answered by playing The Shoot (play the demo. the game really isn't worth $40) and the upcoming Time Crisis.
Even for an adequate title like The Shoot, I didn't have any issues with "lag" or calibration and light gun games are actually an old favorite genre of mine; I've played a lot of them over the years.
The last version of the Gun Con (3) used the same IR based aiming as the Wii, complete with IR LEDs that were positioned on the TV. If the Move based version is the same, I don't see what the complaints could be. I'll wait until Time Crisis fans chip in their 2 cents, but if there are no complaints about the aiming being "laggy" or prone to losing calibration, then I'd have to call concerns completely unwarranted over the hardware.
Any potential issues would lie completely with how developers coded their aiming system.
