To answer some of the questions above.
No, the 1/48 FAST Packs cannot fit in the holes in the 1/60 VF-0S backpack. The holes are too small and have slightly rounded corners as well.
Don't worry about the swing bar on the VF-0S, it's plenty strong enough.
While it's not revolutionary, it's certainly evolutionary in that Yamato have thought of ways to improve nearly every part over the 1/48.
Graham