UPDATE: I laced the Sturmey Archer hub up yesterday, removed the dual ENO freewheels from the old wheel (which was a major PITA btw, it was hell to tap these onto the wheels in the first place and about 3x as hard removing them). After I set everything up, I ran the bike at 8S in the shortest gear and the bike took off like a bat out of hell from a dead-stop. I still pedal-assisted a bit, but with the gearing, it doesn't bog nearly as bad as it did before at all. I took it to WOT in 2nd gear from about 6mph, got off the throttle at about 25mph-ish, switched to the tallest gear and WOT'ed it again and did so all the way up to around 40mph. Running it so hard probably isn't the best way to break it in but this hub does seem really robust but I'm really happy with the results so far.
The power of the motor seems a lot more usable at all speeds now and I've also increased my top speed putting less strain on my system. Probably the best $90 I've spent all year!
The latest versions of Sturmey Archer's 3-speeds seem to be quite an improvement over previous ones. I met a 240+pound rider who uses their SX3 fixie 3-speed hub with a 45t/16t ratio without problems. If torque is what kills gears, I highly doubt any of us will be feeding our hubs as much torque as a fixie rider that size and gear ratio puts through their's.