RE: No more ARF's for me
Sorry about your loss. I know Sig is a good company. 5 years ago I crashed my 4*40 ARF into a tree and broke the wing at the root. I had epoxied the joiner and filled the box with epoxy. The center section was so strong, that I had to saw off the 2 inner rib bays and rebuild the wing a bit shorter because the spars broke off where the joiner box ended.
I think companies like SIG contract out the ARFs to be made overseas with some oversight. But I think that is where a company contracting out the ARFs should have very tight control of the manufacturing process to ensure good quality control. In my case, the ARF was very well built, but in your case, not. That is a quality control issue. It may be that your ARF was made during the time they were having issues between SIG and the manufacturer.
I had called Sig to see if they had ARF wings available, but they didn't. I ordered the kit wing plans and then realized that the kit wing is different than the ARF. So, I think you're right, the original kit design is not the same as the copied ARF design. Factories re-design the plane to make it easier to manufacture.