The main issues with both tempering and mastering can be dissected because there are a few. But i do think the main pain point for most players is that like with most things in this game, enchanting, tempering, and MW are all terribly balanced.
The amount of materials needed to achieve high end master working versus the insane weighted RNG makes it just an unpleasant experience more often than not. Let me run a scenario by the players and ill venture that many of you experienced this:
You’ve been running a rotation for 3 hours of boss runs to gather crystals, hordes for odbucite . and legions for other mats. Then you head over to the crafter to MW that one last piece of gear and you burn through 3 hours of farming in 30 seconds. It just feels bad. Either tone down the RNG or reduce the cost so we can spam the heck out of it , and for gods sake make the temper scroll usable more times.
Its feels more punishing than rewarding. Thanks for coming to my TED talk.