I just want to add that your experience at PVG has much to do with what type of passport or visa you are holding, and how familiar you are with the procedures. For example, if you hold APEC card or newer version Chinese passport, you shouldn't experience much line up at immigration. The dedicated security line for J helps too.

PVG is in no way as good as HKG, ICN, NRT. Even for MU domestic to international transfer you have to claim bags and re-check bags, then go through security again. But a transfer is definitely doable if you prepare before hand. I have done many AC to domestic MU transfers in under 40 minutes.

Speaking about bus gate, that's rare but it does happen. Also PVG is famous for calling Zone 1 and Zone 2 together.