The Byakugan itself ended up being completely dwarfed by the Sharingan in Part 2. And with minimal ninjutsu capability, Neji was permanently in danger, especially given all the methods of stopping him from hitting chakra points. Any sort of shield at all would negate his attack and leave him at considerable risk of death. Aside from Guy, taijutsu specialists have pretty ineffective in part 2, unless they had some sort of mechanism or technique that would ensure that they would survive should their attack fail. This is why Kimimaro had so much potential.