Up to 12G is okay, in a proper body position. Mercury routinely came in at 8G, and those guys were usually trying to control the thing semi-manually, since the automatic systems weren't that good. These days the monkey in the can won't need to do much. The Mercury suborbitals came in at a nice 11-12G.
The difference between Orion and Soyuz is a question of speed; the EFT profile was supposed to simulate a "deep space" reentry, which is faster and steeper than a low-earth-orbit rentry.
You can see the difference in the Apollo program, using the same capsule but with different flight profiles:
Apollo 7 and 9 come in at 3.3G-ish, and the rest 6.5-7G-ish.
If it's actually 8G, that does seem a bit high; but Orion's actually a pretty huge thing, and denser than Apollo, so I guess that makes sense. And they only let the best trained very healthiest multiple-phD government employees ride the thing, so I don't think it's a big deal.
The difference between Orion and Soyuz is a question of speed; the EFT profile was supposed to simulate a "deep space" reentry, which is faster and steeper than a low-earth-orbit rentry.
You can see the difference in the Apollo program, using the same capsule but with different flight profiles:
http://history.nasa.gov/SP-368/s2ch5.htm - Table 2
Apollo 7 and 9 come in at 3.3G-ish, and the rest 6.5-7G-ish.
If it's actually 8G, that does seem a bit high; but Orion's actually a pretty huge thing, and denser than Apollo, so I guess that makes sense. And they only let the best trained very healthiest multiple-phD government employees ride the thing, so I don't think it's a big deal.