I agree that breaking up a context can be viewed as superficial.

But I think it can be worth trying to do it anyway to see what results you're getting out of it.

I have broken up my previous @computer context into:

@vaio

@ios/macosx/

@iPad
@iMac
@iMacV
@iPhone
@macmini
@connected to macmini (screensharing or remote access)
@b ipad (my son's iPad)

@Anydevice/
@search
@mediaplaylist

This has enabled me to think a bit more specifically about how and where I would work on something. The edges between the contexts makes me think differently than just to put an item into a computer context. It forces me to make a decision about what the best place would actually be to do a certain task. That wasn't really the case when I had the computer context. I would just dump stuff there, and they wouldn't get done. I think I get more inspiration about doing the tasks when the computer context has been broken up (down?).