I dunno, it feels... it kinda feels like a wasted enchantment slot. I mean, the real benefit to this enchantment would be to get more enchantment bonus on each individual weapon (once you get past a +3 bonus on each weapon, you're essentially getting free enchantments on both weapons). But I don't feel it actually fixes the whole "TWFers have to spend more gold on their gear" problem.
I mean... ok... at the very least you have to shell out 16,000gp for two +1 Paired Weapons. Then, you shell out another 10,000gp for a Flaming enchantment. And you decide to shell out another 10,000gp on the other weapon for a Corrosive enchantment.
You've just spent 36,000gp on what a THF can get for half that price, because the extra cash you had to pay for the extra double enchantment to link the weapons together. The price eventually evens out somewhere down the line, but it's not going to be especially helpful for anything before level 15.
You could turn the price of the enchantment into a flat cost, but considering you're essentially allowing a pair of weapons to hold more enchantments together than they would individually, I'm not sure it would be cheap regardless. Like I said, the benefit of this enchantment isn't in balancing WBL, it's in giving your weapons a ridiculous number of enhancements.
These are just my thoughts, mind you. There's always the chance that there's a bigger picture I'm not seeing. So feel free to enlighten me if that's the case.