With the input pad off, I felt that many amps were overly distorted at very low volume/drive settings (esp. non-master volume amps). Of course part of the challenge here is that the modelled volume / drive / master volume knob tapers may not match that of the original pots on the physical amp.
With the input pad on, the dynamics, sensitivity and tone are a lot more realistic. The best way I can describe it is that the input pad on seems closer to the real experience and with it off, it's like there's a permanent +6dB boost always engaged (which can be good or bad depending on guitar/signal chain).
At this point, the only way to further reduce signal is post AD converter with a gain block. I was asking if anyone else had tried that and what the results were - good or bad