I don't think she is weak, For them to both speacialize in Taijutsu the outcome of the fight can go both ways. I would have choosed Tsunade because she only needs one punch to strike him with. But Before she can land a hit Neji would do his Air Palm which would knock her off her balance then he will rush in to do His Gentle Fist. Though this is my opinion and prediction of what will happan.Why do people think shes so weak?
Anyway Tsunade.