I always encourage writers to use Emacs and I write in it too. So to have a successful author who uses it to its full potential would be really interesting.
The real killer feature for writers (especially novelists) would be an OS that booted into Emacs and didn't offer any distractions whatsoever. The ironically named selfcontrolapp.com is probably the biggest tech thing to affect the literary scene in a long time...but as a developer I know how to disable the iptables rules in the Linux version. And I have no actual self-control.
I always encourage writers to use Emacs and I write in it too. So to have a successful author who uses it to its full potential would be really interesting.