What I like about TempleOS is that Terry wasn't afraid to make something new and unique, even though it was completely incompatible with everything else.
DolDoc is such a cool idea. Not a unique one, but you don't find many operating systems which have a shell based on that. Since the command output is in DolDoc, you can type `DIR` at the command line and get a list which expands into the whole file tree when you click on it. DolDoc also means that his games have all the images and models embedded in the code, and you can just go there and edit them.
And there are a lot of these. Sure it's clunky and weird and sort of unusable, but I appreciate it for what it is. And I think it's really awesome. Take a look at a random person's osdev project and you'll see mostly the same thing — a unix-like that tries to be compatible with POSIX and port all the utilities. TempleOS is as far from that as you can get (though definitely not unique either).
(Also, a minor correction: TempleOS is not real mode, it runs in full 64-bit mode with symmetric multiprocessing and everything. The text UI isn't the VGA text mode, it's a framebuffer that also displays graphics).