Well, at least he had a better plan than Yara's plan to make the Iron Islands Great Again by building lots of ships.

How hard would it have been to tell Bran "Hey, if you see that white walker, don't freakin' let them touch you!" And jeez, why not give Meera a few dragon glass arrows and put her in front of the tree with the Children. Do that, and the white walkers are all toast.