And he doesn't say whether he was tethering on the iPhone/iPad/Galaxy Nexus, but going over two wireless networks instead of one for the hotspots could also be killer.
Especially the 800 MHz LTE band would have been useful. This band is used in rural Germany to provide LTE based broadband to homes where DSL or cable based internet is unavailable. If the iPhone had supported it you could suddenly have really high bandwidth connections in rural areas where you now only find some crappy EDGE connections.
On another note, I wonder how long until we see dual simultaneous antennas (and modems and whatever it takes) just to win the spec war on this. amazon already did it for Kindle with WiFi.
"Test Results:
iPhone 5 direct via cellular: 4.667Mbps Down & 11.122Mbps Up, 95ms Ping
New iPad via iPhone 5 with Hotspot: 14.10Mbps Down & 1.45Mbps Up, 87ms Ping
New iPad via MiFi 4620L WiFi: 20.08Mbps Down & 8.50Mbps Up, 79ms Ping"