I remember reading on the WMS site that the 5 reel video were meant to be more for the gambler with quieter sounds. Then they found out people didn't like that so they added more music and sounds. The newer 5 reel video titles added bonus music and Carmen and Ming Guardian added reel spin sounds.
As far as that video you posted it looks like a memory or MPU issue which is causing the frame rate to drop, all G+ Deluxe / 5 reel video titles always had sloppy frame rate. Load up a G+ deluxe and when the progressive is within $5 (minor) and $50 (major) the graphic starts swirling around the progressive. This causes major slowdown in the frame rate of the game. Once the progressive hits and the swirling graphic is no longer there, its smooth again. I notice this in the casino and in my home. Seems like the video card, memory, and/or CPU can't handle the large graphics WMS uses in this series. Not a computer expert, just my guess.
I had Hyde, King Midas, and Big Rex (all 5 reel video series) and had no issues. The video you posted, something is either having issues in the cabinet, the progressive could of been "swirling" or just wearing out for being on 24/7.
Either way, these games run fine.