^I've watched a series of youtube vids to see what you mean. The October clips show "C-mode" (no croc or sounds inside), but this one from a few days ago (not sure when it was filmed), does show the croc (but still no audible growls):
To me, it looks like the much darker (naturally lit) cavern makes for a better/scarier experience than the bright caverns of the first months of operation. Of course, the darkness needs to be coupled with a crescendo of growls and a fully-animated Croc to make for the optimum ride experience.
The riders in these vids all seem to quite enjoy the ride and it gets the longest waits in the park (maybe 2nd to Soarin).
I've read that it has had a series of technical issues since previews, so maybe that is ongoing. When the jungle vegetation grows thick and 'wild' and all the kinks get worked out, it looks like a very good rapids attraction to me. One criticism would be the slowdown around the whirlpool before the final drop... feels anticlimactic in the vids. Would be nicer if the raft hit that drop at a clip. I suppose most rapids today can't do that due to pre-drop safety gates. My second critique would be the overly-toonish design of the Croc. Still, I'd give RR high marks as a whole.
Shanghai can get fairly cold in the winter months, but I'm assuming it won't be taken offline this winter.