Gain and level controls on an amplifier-a good thing?

But, If you have high gain noise they are a lifesaver.

Do you mean they have independent gain and level controls, or are you calling them the same thing??

A gain control on a preamp can be really great, since most have too much gain to be useful, and therefore too much noise. It could also change the character of the preamp considerably depending on the setting. 

A level control (simple variable resistor) on an amp can help with channel balance issues, it’s more of a convenience feature installers may like to see.

I had the controls on my Parasound HCA-1000a bypassed and it sounded better...

@jl35 Not really surprised.  For most of us, those level controls are just one more component for the signal to go through.

I think there is nothing wrong with having a volume control, as long the circuit is properly designed. My power amp has one and the manufacturer said some people prefer to not use a preamp, so they are glad to have it. His design is such that if you use a preamp, as I do, and wish to eliminate the amp volume control, to turn it all the way up. This effectively removes it from the circuit. I can verify this as there is a noticeable difference in sound if I don't turn it up fully, it is then obviously engaged. Even though I don't normally utilize the volume control, I am glad to have it as there are some recordings which sound better when I do use it.