Well this is some fairly surprising news to see this morning. The changes during yesterday's PTR patch to the Spellfire and Frozen Shadoweave sets, which reduced their Spell Damage in exchange for Intellect, are going to be reverted before the 2.1 patch is pushed to live realms.
From Eyonix:
The changes players have noticed on the public test realms concerning select tailor-crafted items, such as the Spellfire set, will be reverted before the patch is live on production realms.
This means your item sets will remain just as they are now.
Also note, to address the feedback we've been reading this morning concerning the idea of simply “buffing tier 4 and 5 equivalent slots”, the reason we do not is because improving those 3 slots for tier 4 and 5 would force a change to all other tier 4 and 5 items as well (weapons, melee sets, everything).