Well,
@PENG and others can explain more about slew rate.
But if "Damping Factor" affects the Bass, then "Slew Rate" affects the Treble.
What's also "alarming" is that I can't find any documents that say what the SNR of the Legacy amps is!
For all we know the SNR could be the same as the $500 Crown XLS 2502, which is 103dB at full rated power. The Power output is 440W into 8 ohms and 775W into 4 ohms.