I know this is being downvoted, but there is something to this statement. There's a lot in LaTeX that is getting obsolete and needs to be fixed... I personally think that a JS-based "cleanslate" alternative to LaTeX would be awesome.
I also generally disliked how some features were environments (document, abstract figure) whereas others are commands (sections, subsections, paragraphs, etc). Inconsistencies in what things are passed to various commands as options vs. arguments were irritating, and it's always a bear, for example, if you need to pass say math-ey stuff an argument. E.g. \caption{$a+b$} Nope. Can't do it.
I don't disagree in general about some of the flaws of LaTeX, but am I missing something about this one? Using maths in a caption works fine.
Solution: https://en.wikibooks.org/wiki/LaTeX/Hyperlinks#Problems_with...
There are some clean slate attempts, done with much better languages. See Patoline, for example.