the purpose of agc is meant to maintain the specified level and to achieve this without altering the properties of the source sound.
See, I like the sound-shaping aspect of the multiband AGC. It keeps things sounding more consistent across different styles and formats without needing to use multiband compression.
i can agree with you but to a certain degree, because some musical titles are engineered and mastered a specific way for a specific sound and its not generally the greatest idea to alter/change too much of it otherwise it begins to sound "alienated".
using MB with 100% feedback on 9 bands alleviates the issue of altering the resulting sound too far by allowing a "boost" for those audio frequencies that are below the specified level that you set but not changing them that are above the specified level set.
the ending result is a cleaner, fuller and more vibrant sound that still retains the same engineering and mastering qualities and dynamics as the source.
this type of method can be tested over from MB to MB and the change is minimal to none, meaning if i save a tune processed in this manner as WAV and then play the tune through ST a second time, it wont be processed "double" since those resulting levels are already at the same specified level and MB ignores it.
i like to think of it as a "regulator" for audio frequencies in 9 bands.