I’ve seen a lot of people asking for uses for blue and yellow items.
One possible use would be allowing blues to drop with greater affixes and allowing tempering post master working.
This would give you the ability to guarantee boosting a particular affix at the expense of master working your tempered affixes and loosing two Lego affixes.
It might also be nice to allow them to be imprinted and have a cheaper master working cost. Maybe even a more common resource for master working to allow it earlier in the game.