Alright, so I work as a mathematician and I'll strongly agree that there's not good substitute for TeX at the moment for producing mathematical documents. That said, I do periodically look for something better because it's far from perfect. In large documents, I find it difficult to produce easily maintainable mathematical statements since the macro situation in LaTeX is a complete mess. Often times, I have a large formulation that I want to modify only a small part. Now, yes, we could just number all of the equations, change one of them, and then say that the result is the combination of (4), (27), (43), and (45). In fact, we can link them, so that everyone could flip back to these equations. That also makes really hateful to read documents. Really, I want to display all of the equations and I don't want to retype them since I may very well make a mistake and I want that correction propagated around the document. So, we can use macros to help with this, but the definitions have to occur before \begin{document}, which is not where I want to look for an equation. I want a local definition since it's next to what I'm looking at. We could use something like \newsavebox, which I often do, but I often want to just make a reference to part of an equation and this is not a good solution for that. Maybe there's a better macro or way to do that out there, and if anyone knows, I'd love to hear. I could write my own macros, but, really, I find TeX to be a difficult language to work with. I am curious to know if LuaTeX makes this much easier to do and I've been meaning to experiment to find out.
So, yes, in a vacuum I think that math notation in LaTeX works really, really well. However, for a larger document, there's a lot of other features that would be nice to have and they're difficult to implement in TeX.
So, yes, in a vacuum I think that math notation in LaTeX works really, really well. However, for a larger document, there's a lot of other features that would be nice to have and they're difficult to implement in TeX.