Right now the enchanting system have too much variables roll and % range. For example if I roll a purple rarity item., positive stats perks are too low % while the negative % are too high. The item will not let me even pause and consider it.
Meaning the rolls % values of negative vs positive affix should be considered in the coding when such rolls pop out. So it can makes the player give a 2nd or 3rd look deciding whether he/she would want to keep it or not instead of trashing it immediately.
Also the shield should be able to have rune slots like the bow or torch. And shield purple affixes. are not as strong as the blue affixes.
I highly suggest that the game should introduce various materials dropped from elite mobs. you can make it have a chance drop %.
This new resources will be tied to the enchanting system to let players use different types to lock one affix in but not lock the range % and rarity.
In that way you give the player the opportunity to farm the resources on top of exploring the open world etc.