I came to Sonar with X1 so I have no experience of the pre-ProChannel days. To be honest I've never really used the regular FX bins - I'm a big user of ProChannel modules and to mix the ProChannel with the FX bin seems illogical and awkward to me so I just left it alone. I found the thread I was talking about earlier in which Noel offers an explanation. He says "
The idea behind FXChains is to provide a composite object that hides the underlying effects. There is no way via ACT to switch between the chain parameters and the constituent effects. Even if we did that (which would be complex) it would be pretty confusing to know what the current context was via an act surface."
http://forum.cakewalk.com/FindPost/2407093 I understand the thinking behind FX Chains being a composite object in the context of the FX bin. But ideally this philosophy should be updated for the context of the ProChannel. In an FX bin, there's no other reason to have them. But in the ProChannel they serve a wider purpose, which is surely to provide a way to insert regular VST's in the channel. After all this is the only way to use regular VST's in the ProChannel. Therefore, any VST's within the ProChannel should be treated as VST's anywhere else, i.e. effects in their own right and not just part of some composite object. Of course the "composite object" convenience is still there if you need it.
I'm not a programmer and even if I was I would have no idea of the way these things are implemented in Sonar at the code level, but I'm having trouble imagining why it would be complex or confusing for Sonar to know what the "current context" was via an ACT surface. After all, how is the current context decided in other cases? By whatever is in focus? Surely FX Chain VST's in the ProChannel can be given focus too - you can select them within the ProChannel, or you can open their GUI's and click on them.