TexMaths is a great addition to libreoffice. Working with complicated equations, though, can be tricky due to missing syntax highlighting or error checking.
A way around that might be to allow equations to be created from an external tex file, that can be edited using a proper TeX editor.
Example work flow:
1. Having a tex document with labelled equations, the user could specify the tex file and the equation label in the TexMaths interface.
2. TexMaths extracts this equation from the file and creates an TexMaths equation object.
3. As additional information the equation label and even the tex-file name could be embedded in the meta data of the equation image, so that even updating the equation from file could be done as well.
Yes, it could be done, but in this case TexMaths would be tight to an external tool, that should be compiled on the three platforms and maintained as well. So, too much pain for the benefit IMHO.