Well, I said the same in 1997 when the share price was $13 and that was before two stock splits. I hate myself for being too chicken to spend all my savings on buying stock back then. I could be a millionaire now without lifting as much as a finger.
iPhone tethering an MBA works just fine, both over USB and Bluetooth, provided your carrier supports tethering in the first place. This however is hardly Apple's problem.
I've been using my Air coupled with the iPhone many times. And the data volume is not significantly higher on the Air than on the iPhone, as long as you stick to the same tasks.
Maybe that's not the SIM slot but the cable connector? There doesn't seem to be a slot for that on the bottom, so maybe they swapped it around? Would actually make sense if you want to play games on the device: hold it horizontally and have it plugged in for continuous power without having the cable in the way.
I did until about 4 weeks ago when I got an offer for a second hand 3GS that I simply could not refuse. What a difference. The 3G I got the day it came out here in Switzerland had become unbearable.
Now I guess I'm going to wait for the 5G or even 6G, depending on how the 3GS continues to perform with subsequent updates.