No that's a good decision. He show great leader by giving a good position to whatshisname. Old guy hated Jon, but he cares for the protection of the wall and is a good warrior. Headless guy was just a conniving piece of crap, that couldn't fight at all and was just taking resources for other people,like food and clothing.
He gave the guy a different order, but he decided to talk shit to his leaders, if Jon didn't do anything he would appear weak.
He got the respect of his men and stannis. That might still come back to bite him in the ass, because in westeros, they are no action without Consequences in there.
Also he did good, requesting people from families and factions that betrayed has family. The wall needs all the men it can get.