Rikki, latency is primarily a problem if you are going to play live. If you are just going to produce midi tracks and mp3s from that, latency may not be an issue for you.

The sound quality of the softsynth you used with BIAB is likely the 4 mb version. This would be relatively very low quality when compared to your KN. I do not think the laptop soundcard is the issue. Your built in laptop soundcards only become an issue if you need low latency and very high quality sound. Sound quality that is say better than your KN. Another issue may be using XG voices on a GM/GS wavetable. You could end up with dogs howling while rendering a romantic ballad and your love ones wondering whether you finally lost it - very sad!!!

Rikki, you just have to get used to a different control system. Just sell your KN as a spare to UD and start a new life!!! As you know you can program the lower octave of your keyboard to control the fills, variations, endings and so on. I use the Roland A-37 midi controller keyboard and after 2 or so years I am very used to this approach. You are right, there are some compromises with the control surface but I am certain you would get used to them?