I do not believe that the problem is fundamentally about space, but rather is a cultural problem that stems from three things:
- Reviewers do not demand clarity in their mathematics
- There is often a perception that "fancy" or "difficult" math means more important science (related to #1)
- Really clear presentation of mathematics is difficult and takes a lot of work
("I would have written a shorter letter, but I did not have the time.")
Ultimately, a community tends to get what it rewards. There is no reason that math must be impenetrable. Even if one is faced with a space problem, you can play the same sort of games that you do with figures and data in order to fit. Right now, however, it is typically understood and accepted that you don't have to do that with your mathematics. In fact, some scientific communities will punish a researcher for presenting mathematics more clearly, because it makes the work look "less significant."
Technology cannot help solve this, because ultimately it is a problem of human communication. Anyone who is bothered by mathematical impenetrability can, however, take their own small steps towards changing this culture:
In your own work:
- Include tables and clear explanations in your papers.
- Use as few symbols as possible, and choose the symbols to improve clarity, e.g., matching the symbol to the first letter of its description.
- Buffer your equations with explanatory prose that restates their content in plain English.
When considering other people's work:
- Call out mathematical impenetrability as a reviewer
- Ask for tables, clear prose, etc. in the papers that you review
- View the mathematical impenetrability of a work as a flaw rather than a good thing.
This is a very difficult problem, and unlikely to change any time soon, but it can be made better one paper at a time. Moreover, it is my belief (and experience), that clearer mathematics can make for a higher impact and better cited paper, so it will likely be valuable to you in the short term as well, unless you are in a community that has a toxic relationship to mathematical impenetrability.
todonotespackage may work better. You can add permanent "bubbles" to the output in the margins. Obviously the intended use is to put in todo-notes for oneself, but it may work for this case as well :-)