I wouldn't call not letting your main forces know that reinforcement could be on the way, avoiding hundreds if not thousands of death to be good leadership.
Self serving, power grab and smart in a "let's fuck any pretention my Brother could have to the North with his Wildling army and Giant", sure.
Putting qualifiers, I would say (not in order of skill)
Best plotters: Cercei, Tywinn (deceased), Margery, High Sparrow, Olenna, Littlefinger
Best inspirational leader: Dany, Ned (deceased)
Best strategists: Rob (deceased), Jaime, Ser Davos, Tyrion, Yara
Best field fighters/ tacticans: Hound, Mountain, Oberyn (deceased), Jaime (two hands), Jon, Brienne, Loras
Best guerilla fighters: Bronn, Vipers, Daario, Yara
Imo for the ultimate army facing the WW, you should have Dany as inspiration, Jaime general, Brienne and Jon field commanders, and Bronn/ Yara leading guerilla units.