I don't think you needed to nerf the physicals from the 9-15 baseline with these gauntlets. I kinda like the idea though, but defensively they are so weak that I would not wear them on my current bard, even before Paragon loot. Bards are already semi-cornered with immunities itemization wise, so I don't think it's possible to wear these un-augmentable, low immunity gloves. Perhaps XR items would allow it, not sure.
On another note, I would try to hit a "deafening clang" buffer item with caster slots to avoid it becoming the mandatory swap-for-buffs item. Not sure if you agree - just an idea.
Edit: i'm wearing augmented Manacles on mine for spellimm 6, 25% fire, 5% mag, with a Prideleader's augmenter for 20% sonic and fear immunity, with upwards physical randomize - for clarification what these would fight to replace. And I -know- there are plenty of people with better gloves out there.
I can see adding some bard slots to it, just didnt seem right that neither the BUR, or XR alternatives had any. Optionally, remove the clang idea and make Amplify an AoE like Visor of Cursed Chaos and BC.