I was thinking and I have seen some complaining about tinkers and them not being a combat guild. I personally don't see how that is in this game or even in the fantasy setting. In my eyes tinkers are lazier fighters. But anyways that is just a rant.
My thoughts would be to get rid of balance weapon from the tinkers and add a skill Augment weapon or something to that effect. What this skill would do is make the weapon that is runed/chanted better. This would only be useable for the tinker and would make the weapon useless in someone elses hands. There would be some prereqs for this skill. Something to the extent of 200 wield, so many skills at 150% and it would be a level 40 skill. This skill would also have a cost like 12-15 to train.