I agree that Jon hasn't been a great battle commander. I think his bad decisions were made dramatic purposes. Against Ramsey, Jon's rash decision enabled the Knights of the Vale to sweep in for the save. Against the Army of the Dead, the destruction of the Dothraki, who were previously unbeatable in the open field, raised the stakes of the coming battle.
More importantly, assuming the Dany/Jon coalition defeats Cersei and the Golden Army, Westeros won't have a huge khallasar roaming and raiding its lands.