Don't know, but I've seen a similar thing since switching from DSL to cable. Just plugging the router into the cable modem instead of the DSL modem cuts the download speed in half. Other Android devices and PCs have no download issues.
I've run tests with the
M-Lab client and it shows that many networking parameters (buffer sizes etc) are different on the N7 and other Android devices, but I don't have enough network-fu to figure out what they mean. Nor is it likely that there would be any easy non-root fix to a networking parameter if I did figure out what the problem was.