What a wonderfully educated post. 
Very refreshing
This seems very similar to the issue I had when testing the Netgear CG3000-D. It was later resolved with a firmware update but the first 2 weeks were horrible. Hopefully one of the moderators can check your firmware and see if there is a update they can push.
The odd thing is your data supports a issue with the gateway, but you said you had the same issue with your previous set up? Could there be some environment condition causing the issue to occur on both pieces of equipment? EMI? Overheating? Etc? Or do you think they are two separate problems? Do you have any data from the problem on the original hardware?
Overall though, I think you would be much better off using a modem and separate router. I don't like my ISP controlling the firmware of my router for so many reasons, from performance to privacy concerns. Also, in general, the hardware found in gateways is usually the manufactures basement bargains.