JasonPlitt, thanks for your report, what's you're describing is the behavior that we get in overheating conditions. In normal conditions, the computer doesn't overheat in any of our tests. So changing the minimum requirements doesn't make sense.
The temperature is not a good way to know if you're overheating or not since OSX will slow down your computer to keep everything safe. The result is that the temperature won't change that much.
Multiple causes are possible. Your room is too hot(>80F), your fans/vents are dirty, your fans are not functioning correctly, the vents(keyboard and back of the hinge) are blocked.
In our tests, we need to block the vents and play in a rooms at over 80F to get the problem that you're describing. However, I'm guessing that you're not playing under these conditions.
So can you describe the conditions that you're playing in?
Do you play on a table?
Do you plug in the power adapter?
Are there any other apps running(check Activity Monitor for anything above 5%)?
If the computer is cold, how long does it take to reproduce your problem?
I play on a flat wooden table with my MagSafe plugged in (I *never* play on battery power), and temperature in my living room is ~70 degrees F. These are the conditions that I normally play in, probably 99% of the time. During a few 5-stack Warden/Butcher runs on my barb that I got done with a few mins ago (no cycling, no framerate taking a dump...I've had ZERO problems since I implemented the Machkhan trick, even during the 2 simultaneous elite packs, including Illusionist and Horde affixes, so a lot of crap on-screen), I would occasionally play in Windowed mode so as to take some peeks @ Activity Monitor. The only process consistently over 5% was D3 itself, pretty much steady @ ~12%. Kernel_task would fluctuate between ~3.2-6.3%. Agent went as high as 4.7, but never touched 5. I did have Safari running in the background also, but both the Safari and Safari Web Content processes never went above 3%. No other processes even came close. But this is the only significant period (Machkhan fix) that I have been able to play since before a few days after release. I don't know why it's working now, but I'm not going to question it. I hope this helps :3
EDIT: I'd also like to add that SMC temps were the same as previously reported; total playtime, including periods of sitting around doing nothing in-game to take longer looks at Activity Monitor, was approximately 2 1/2 hours. I'll be playing for much longer periods of time this weekend, so I'll report back with my findings during those times.