While killing enemies in the Infernal Horde, build up an energy bar / currency (Aether) or something similar.
The waves should spawn when the previous wave dies, so the quicker that you kill things the more you build up your bar.
At the end once you’ve killed the bosses, you get 2 Pedestals you can use.
1 of them is a Re-Temper pedestal.
1 of them is an Upgrade-Temper pedestal.
Based on your energy bar earned during the event (which would scale with the tiers), you get a charge you can use on these pedestals.
It could be the equivalent of getting 100 Aether you get the ‘Re-Temper’ 1 affix on 1 item to a SPECIFIC temper, and it will roll a % based on how much energy you earnt.
If you go beyond a certain amount of energy, you get a 2nd charge, up to maybe a maximum of 3-4 charges, and your energy is ‘used’ after each, so the first might be 100% but the next might be 23% and that’s it.
The 2nd pedestal would let you ‘upgrade’ an existing tempers value. If the current roll is at 50% then you would need enough energy (50% worth) to upgrade to 100%.
This way, IH would be meaningful, but not mandatory.
It would use a tempering charge on your item, so if you get a 3GA item, you would run IH before doing any tempering, so that you can roll the affix you want, then upgrade it to max etc…
If you don’t need to use the tempering pedestals, then you can open a masterworking cache where you get masterworking materials based on the energy you collected, similar to how the gold chest currently works.
Thoughts?