Earlier quoted context omitted.
I am curious what the upside of doing so would be.
I'd like to see graphics inline, for example. Another one: in Emacs, to display inline docs, you either use the modeline, or a buffer, or a tooltip. It could be nicer... The amount of hackyness needed for adding something like a Markdown preview bothers me.. To me, LT could be Emacs with better rendering. I really enjoyed learning Emacs, its a great design, like an open-world game. I want more apps to capture that.
Inline documentation doesn't seem all that desirable in the first place; from the screenshots I've seen, it looks like it would get in the way, which documentation in a separate buffer doesn't do. (I'm half tempted to implement inline documentation for Emacs Lisp mode as a proof of concept, mind you, but I really don't see the point of it.)