Decaying Hex not affected by damage modifiers

The support gem Decaying Hex attaches to a curse spell to add Chaos damage equal to the character's Intelligence. This is presumably to keep its damage increasing roughly in step with skill gem upgrades, which for a while was making Conductivity and Despair my favorite spells. But unfortunately, Decaying Hex seems to be completely unaffected by Damage, Spell Damage, and Chaos Damage bonuses. Seeing as a character's Intelligence doesn't increase in anywhere near the exponential fashion as damage bonuses, this makes Decaying Hex increasingly irrelevant as the game progresses, to the point that it was getting a little unreliable before I'd even reached Cruel mode.

I couldn't say whether enabling damage modifiers on Decaying Hex might require nerfing its base damage to keep it in line with other endgame content, but I can say that Decaying Hex needs to be affected by modifiers in order to be useful. Please take this into consideration.