I agree X2, we have to work with what we have, you rare on the money with the concept of determining the bottleneck and finding ways to overcome that.
My issue was I was not sending data to tape fast enough, and I had drives locked for long periods writing slow backups. Sending data to disk first eliminated the drive locks, and the disk array sends to tape much faster - in fact, I was using LTO2 drives because we could not send data fast enough - now I am driving LTO5, so everything is faster.
Break your process down to steps and figure out how you can improve those steps.