Everything the author describes lacking in the end exists in emacs. Come on in, the water is fine.
Looking at how insanely fast competent line staff are with terminal interfaces like in retail POS settings, I sometimes wonder if Emacs would be fast enough to keep up with them. If so, instead of using a browser as the base UI framework, would a terminal-screened Emacs (that is, in console mode or perhaps inside xterm, and not the graphical Emacsen) with an appropriate text UI library be feasible?
It can't possibly be worth the effort unless the text UI in the code is the only presentation layer, I'd imagine. But if you have to go down that route, it might be faster and easier than rolling your own termcap-based text UI, especially with all the elisp goodness within. The only extensive text UI I knew of was Vermont Views' product, which has since disappeared off the Net and was closed source anyways. There are some open source libraries, but none with nearly the power that came with that closed source offering, and all still quite low level.