If the regulars still came as regularly as they used to it'd still be rocking. If regulars only turn up every so often, it looks like not much is happening, so the fringe people drop off.
Yeah they re-recorded it for UA. Its copped alot of flack from some quarters for various reasons but having never heard the original I find myself enjoying it. I'm warming to the entire album and its the first 'Deth album I've had time for since RIP. However I agree that without the re-recording the album would've been a harder hitter.