Runescape passive effects on weapons

It was great when you guys added the passive effects to the god swords to help restore some of there previous abilities, why not do the same thing with the old weapons such as the dragon dagger, dark bow, chaotic/dragon claws, staff of light etc….. this is better than rendering these weapons completely useless. plus it would make things such as slayer more worthwhile and make the rs economy better.

Example: staff of light passive effect 1/4 chance if your enemy is using melee they will only hit 50 percent of what they are suppose too.

It would be great if you guys could add things like this too new weapons also, kalphite king weapons etc.