Kit vs ARF
You can always pick examples to bolster claims either way. Pick a bad kit, and even cheapo Vmar ARFs look great in comparison.
*THE* most important benefit with ARFs, besides faster time to RTF, is that the first 90% of construction is of known and constant quality. I am sure an expert builder with time to burn can build better, but most ARFs today are built better and straighter than the average kit builder can muster.
As for the fuse strength issue above. The kit way of fitting wing to fuse looks like a pain in the neck - certainly very unconventional. Don't know how the ARF version wing mounts to the fuse, but more than likely the wing is used as a stress member so the fuse section near the wing doesn't need to be quite as strong.
Many motorcycles use the engine as a stress member as part of the chassis. Look at Ducatis with the Desmo twins, or the Yamaha Viragos. If you take the engines out of these bikes, the frames don't look like much. It's actually a very efficient design.