I have a related feeling about TeX. It has superb output quality but the programming is awful. When LuaTeX finally arrived a few years ago, it was possible to do almost everything you have done before in the TeX language (starting with \backslashes) in Lua.
I have (shameless plug) created a database publishing software using this technique (https://github.com/speedata/publisher/). Once in a while I have to use LaTeX and it feels a bit old school to do the macro programming.
My next project is to rewrite the TeX algorithms in Go - see https://github.com/speedata/boxesandglue. Already usable but not TeX like in any way (this is just a library, not a frontend software like TeX)
I feel the same way! I also feel like the LaTeX crap on top of Plain TeX is crap and it fills me with rage when I try to find info about TeX and always get back something assuming LaTeX.
Various senses that concur.
It has, in addition to the line-breaking algorithm, a global page-breaking algorithm ... and for the rest may I suggest reading (it's brief) section 4.2 of GNU TeXmacs, A free, structured, wysiwyg and technical text editor, J. Van der Hoeven, Cahiers GUTenberg, no. 39-40 (2001), pp. 39-50, that you can find at the official website of the journal at http://www.numdam.org/article/CG_2001___39-40_39_0.pdf
See http://wiki.luatex.org/index.php/TeX_without_TeX for an introduction.
I have (shameless plug) created a database publishing software using this technique (https://github.com/speedata/publisher/). Once in a while I have to use LaTeX and it feels a bit old school to do the macro programming.
My next project is to rewrite the TeX algorithms in Go - see https://github.com/speedata/boxesandglue. Already usable but not TeX like in any way (this is just a library, not a frontend software like TeX)