Thanks for your posts guys. The that surprised me most was that, before the 2.0 update, I was using the DT probably without realising there was a cab sim on. I'm pretty experienced using modelling live (traditionally amplitube into an acoustic image and my THD cab) and when things sound a bit funny, the first thing I do is make sure the cab sim is off. Switch the cab sim off and everything comes right. I've got a pod HD500 and always just made sure the can sim was off if I was using a guitar cabinet. I'd read that they were 'live' models if not if studio/direct mode but was not convinced. I think I've changed my mind a bit, 'cause the DT has always sounded REALLY good, and I've had 'live' cab sims on without realising it!
BTW, I don't use the pod with the DT using the line6 connect. I've always wanted to be able to call up different patches with the amp settings not changing. On a gig, I want to be able to change the amp eq and have it 'stick' when I change patches to use different effects chains. Having the pod with only effects running and using the preamp sims on the DT is the perfect setup for me.
I have some experience as a software developer and have always thought patch systems on things like the pod could be made a lot better by allowing a hierarchy of patches. So, for example, I could have a 'parent' patch that has , say, an amp setup with maybe some reverb and eq. I could then apply a 'child' patch that has maybe some chorus or a drive pedal. Then I could change the child patch, but retain the amp settings and reverb from the parent patch. This is actually a pretty common way of dealing with settings in software. The active settings are calculated from a hierarchical structure with certain rules for overriding or combining settings further up the hierarchy applied. That's the way I'd do it.