Yeah, me too. The idea of "amp line out > 2i4 > laptop" is really intriguing. It should be pretty easy to control a) noise, and b) recording levels. With my current setup, Zoom B3 > laptop, I get lots of hiss, with a very weak, but clipped bass sound in the track.
Ok, I got my 2i4, and set it up exactly as I posted: amp line out > 2i4 > laptop. I did some quick recordings with Reaper and with Kristal AE, and the recording levels are great now. But I'm still getting a lot of hiss, and occasionally in the middle of a track, the volume level drops down about 50%, and everything sounds like it's underwater for a few seconds. I'm not sure what's up, but I'm guessing it's the laptop. I may try downloading Kristal to my desktop, and trying it there.