Of recent attempts at dethroning LaTeX, there's also SILE, which actually reuses some LaTeX internals. For some examples of the output (hard to find, the author seems not great at marketing), see e.g.:
https://github.com/simoncozens/sile/blob/master/examples/ara...
https://github.com/simoncozens/sile/blob/master/examples/art...
https://github.com/simoncozens/sile/blob/master/examples/fra...
https://github.com/simoncozens/sile/blob/master/examples/par...
https://github.com/simoncozens/sile/blob/master/examples/jap...
https://github.com/simoncozens/sile/blob/master/examples/tes...
For a deeper dive, see the author's presentation at FOSDEM 2015 - I found it really amusing - from the starting line of: "I wrote a typesetting system - by mistake."