Are you saying that if you were the head of SI you would have no problem sending someone who looks...ahem...as healthy as the way McCoy did in Encounter at Farpoint, on a mission into enemy territory like he was some kind of commando ? Chekov was roughly the same age in the V-Soul trilogy as McCoy was in EaF. Uhura's reasoning behind getting Chekov was that he was the only command officer in Starfleet who had encountered them, but he still didn't know anything of any relevance. Having him in contact with Saavik's ship wouldn't have been a bad idea, but going on the actual mission to meet the Watraii seems ludacrous to me. I find it hard to believe that with all of SI within Uhura's grasp, that the best person for a massively important mission into enemy territory, was a man with next to no knowledge about said enemy who also happened to be 132 . Remember...it says that Chekov had met a Watraii over a comm channel for a few minutes or so several years prior to the setting of the story. He had never had any real or relevant experience with them.