As he mentions, zsh also knows argument semantics. So does bash. He never explains how Bespin implements this feature, but I don't see how you can get a significant improvement on the way these shells do it (which he says is probably not the best way) without abandoning the standard toolchain altogether. (zsh uses scripts to do it, which can use --help output if desired. ISTR that they're rather complicated, but then they're also rather powerful. I think they become much simpler in degenerate cases, but I've only ever dabbled and that was over a year ago.)
For the pipe inspection, I got the impression he might have been talking about "look at the data that's being sent". Which can be done with tee, but both that and pv require that you insert them into the chain beforehand. I think there's room for improvement there. (I suspect it's possible to do something with /proc/$$/fd, but I'm not sure and I wouldn't know how.)
I do think shells and terminal emulators should interact better with each other. I often wish my rxvt knew about my GNU screen windows, so that the scrollbar and mouse wheel worked consistently and I could navigate tabs on the status bar by clicking on them.
For the pipe inspection, I got the impression he might have been talking about "look at the data that's being sent". Which can be done with tee, but both that and pv require that you insert them into the chain beforehand. I think there's room for improvement there. (I suspect it's possible to do something with /proc/$$/fd, but I'm not sure and I wouldn't know how.)
I do think shells and terminal emulators should interact better with each other. I often wish my rxvt knew about my GNU screen windows, so that the scrollbar and mouse wheel worked consistently and I could navigate tabs on the status bar by clicking on them.