No I don't think that's true at all. I've seen beautiful images shot with the D2X and blown up large, and they're selling a lot of those cameras to a lot of working pros. There were other issues for me.....
1) the depth of field of a 2/3 chip camera is greater than that of a full frame when looking at the same framing. Because the chip produces a smaller image, you have to move 50% farther from the subject to fill the frame the same as you would on a full-size chip. That increases the sharpness behind the subject. If you didn't move, you'd have to use a lens 2/3 the focal length of the one you intended to use, which also increases the sharpness behind the subject, and I prefer shallow (less sharpness) depth of field for my model shots.
2) The working distance to the model is therefore farther using the same lens, when trying for a certain perspective. I often found myself farther from the model than I wanted to be, or if I was working in an enclosed space, having to get a wider lens. Some if it just takes getting used to, but I always seemed to be too close or too far, and I preferred to go to a format I've got ingrained in me after 35 years of shooting (since I was a baby!)
3) The D2X is more expensive than the Canon 5D, which reallly mattered more when I was considering what to do for a backup body. At the time, my backup for the D2X was my D70, which wasn't really up to the task if I really got stuck on an island somewhere, so my only other option was another $5000 D2X (today, I would consider the soon to be released D200 as a backup). When the 5D came out at $3300, it was conceivable I could afford two bodies, but since then decided for now I'll use a 20D for backup (just bought one on Ebay) and as a bonus, for some types of shoots where file size is not critical, and I don't want to drag the heavier, more expensive 5D around. I have never been a fan of buying an expensive camera (or anything really) when a less-expensive one will do the job. (And BTW, the D2X is loaded with features I'll never need as well, and I kind of resented paying for those). For years I shot all my stock for calendars and posters and such on a Nikon F100 film camera, which cost a heck of a lot less than the Nikon F5 which did all sorts of things I didn't need, but the F100 did what I needed extremely well, and with a lot less weight (another issue for me). In a nutshell, in your considering which camera to go with, I wouldn't let the size of the chip in the Nikon be too much of an influence, because it produces a very good image (I've seen test analysis samples where it looks better than the Canon 1DsM2).
Hope that helps,
Andy Pearlman Studio