gswitz
It would be kinda cool to set up the footswitch for the alpha track to switch through different TH2 Amps etc. Wouldn't it? Could that work? Might take an afternoon's effort, but it would be cool. I'm not sure why doing live work outside of Sonar would be better, especially if sonar enabled me to use midi devices to automate the plug-in.
Ah, I didn't know you could do that. Cool! Then to answer your first question: I don't think you'll see any benefits of installing anything else. Unless you want to plug in your geetar and shredd to your hearts content without launcing your DAW
I've mapped my Novation Nocturne controller via MIDI to many of the functions. Another big pluss for TH2. It's a helluva lot easier to do in TH2 than any other amp sim I've used! It also works really well with Automap. I don't have any footcontrollers but I'm starting to get an itch for that too:p
BTW - I can really recomend the Mark Studio 2 as well if you're into bass. I'm a bass player and a Mark Bass fan and I'm so glad I got a good deal for it at overloud.com. It sounds great on my basses and I've used it on some double bass patches in Trillian as well with pretty cool results.