tempering needs to change ....

It feels really bad when you get a rare drop (e.g. amulet with GA passive) and then you miss all the tempering.

It just happened to me and I have to live with bad/suboptimal tempering. The amulet is still an upgrade, but that is not the point. It was a "OMG .. YES" feel good moment .. and then it became a fee bad moment.

A ARPG should only have feel good moments. You can make it very rare (again, like amulet GA on a rare passive) but it only adds frustration even if there is a chance that tempering will brick it or lock in bad choices.

When I got the right tempering, it is not a feel-good moment, it is a feel-relief moment. Heck, make the cost of restoration (of tempering charges) increasing. Cost 2 potion the second time you unbrick. Cost 3 potion the 3rd. Etc. But as long as there is a way to unbrick, even if it takes some grinding, it will take away the bad feelings.