For a system to exist that grants players as much power as Tempering does, there has to be a great risk for it as well. Even without seasonal powers, players are more powerful now than most any season previous to this one because of Tempering.
The only way we should be allowed to reset tempers, is if they lower the rolls on all the tempers to make it not as powerful. Otherwise, we only need to find a semi-decent 2/3 item to have a really good 5/5. That’s just way too easy for something that is almost way too powerful.