I'd think the rc0 system was developed to handle larger cameras, possibly view cameras or larger film cameras, tlrs, etc. Many of these are much larger in size (if not necessarily weight and leverage issues) so the larger plate allowed more contact space in both the mounts and the cameras bases. Not sure it's needed in "35mm" size camera bases, and the extra size where it extends past the camera edges seems to be bothersome for packing and for carrying.
The rc2 is not that costly, the folks that say "wait" can't be serious. They aren't really suggesting do without a qr system completely. If you want the 468 head, then consider the rc2 bae. The real step up with the Arca Swiss system is to get a functional and well designed "L" bracket. The rc2 is adequate for some use on portrait and most of the lenses that begin to get seriously heavy or long are equipped with collars.
I may be wrong, and its been a while since I've used the RC2 plates, but I dont think there are any of the plates that stop the twisting on the camera. That is the benefit of plates made for the particular body. I do believe some people have modified them to fix this problem.
I can't comment on the rc0 system except to say what folks have said above seems to be the comments I've heard from people with that system. I've never used it as the heads I have are rc2 heads. I haven't experienced twisting on the plates with the gear I have but there is some "sag" with some of my tripods/heads as they whole system has some give and the leverage is more pronounced when in "portrait." The 3030 (pan/tilt) doesn't seem to give much at all on my heavy Giottos legs (if the different axes are tight). The 3265 pistol grip and 725b are saggy in portrait with a heavy dslr and pretty much any lens. But that's not twisty so much as sag. You do need to be sure the plate is snugged down in the heads as well, there can be some give as you set it up.
There is a solution to this. Buy second hand. I bought all my gear second hand, including a Gitzo 2228 and RRS BH-40. You will save a lot of money. You could pick a 055 up for 70-100 depending on the model and still have money to buy an Kirk BH-3 or possibly an RRS BH-40. The difficulty is you will ahve to be patient.
