I believe 6s was the fastest ever too, but it was only 13 days after the launch. We are now at 14 days. Fingers crossed.
First there's the principle: If I'm paying full price for an unlocked phone, I shouldn't be required to sign into/give my existing carrier account info (the rest of the world doesn't have to, just US).
Secondly, I have AT&T, but I don't want the AT&T version that is limited to GSM. Like you noted, I'd love to have the Verizon version that has both GSM and CDMA should I ever decide to switch carriers or to have a better re-sale value down the road. Until a SIM free version is released, I am unable to buy a Verizon version without an existing Verizon account even though I'm paying full price up front. Both models cost the same, so I should have my choice, not be subject to arbitrary carrier collusion rules. Unacceptable.