I think one of the problems with the Spirit Spear is its never had a build up to be sold as why its cool.
Priest worked to sell those energy dagger. Same with the thrice blessed armor. I think EMH showed how versatile the daggers can be. The spear is just kinda there. If it had a training component to it like Kuwabara's spirit sword, and expanded it to beyond throwing and the target falls down, then it might have more of a wow factor.