i agree, they embed the chakra into things and body parts, like water, air, and their hands and feet, i dont think the rain ninja was guiding the needles with his chakra, i'd have to go bakc to make sure, gaaras sand is controlled by him but thru demonic powers, the priest spirit gives him the ability to do what he does, temari, it'd seem to me that she puts her chakra out into the wind that she thrusts out from her fan and causes them to form blades and from the speed of the wind pushing them it becomes damaging, if u could embed chakra into weapons and guide them to the people i think no one would miss, also, who's to say that if u could get ur chakra into a weapon u'd be able to make it move where u want it to go, this isnt quite dbz, u cant just telepathically control chakra u've already manifested outta ur body, or at least they dont give us any examples of that anyways, if that were the case u'd have dbz on ur hands cuz all it'd make sense to do is spit out a ball of chakra and send it at ur opponent and make sure it hits, and we dont want a dbz coming outta our naruto

p.s. - the only example i've seen of someone controlling something that was thrown was sasuke with the sharingan controlled shurikens and we already know hes got strings attached