...
To display algebra on screen
Well formed Greek letters (e.g. Times New Roman).
Also well formed English letters, in particular "l" (twelfth letter of Latin alphabet) should look different to "1" (digit between 0 and 2). A looped l may be a necessary addition.
Include options for changing colour for those who need e.g. high contrast.
Font sizes should be suitable for browser commands that enlarge text.
To enter algebra from the button bar (a "palette")
The generally accepted full set of symbols and operations (as found in other equation editors) - see sub-pages.
Students can use equation editor to enter algebraic answers to questions.
Students can enter an algebraic answer AND have a separate box in which to enter "workings" (i.e. several equations showing how they reached the answer) [examiners will be able to see these and award partial marks].
Users can run from keyboard (e.g. via tab and arrow keys).
To enter algebra as LaTeX
LaTeX will allow authors use of all symbols including those not specified through the palette (we do not expect higher level mathematics to be entered through the palette).
For the equation editor to be part of the TinyMCE [the native WYSIWYG editor found in many applications]
For the equation editor to work with Maxima [a system for manipulation of algebraic and numerical expressions]
An equation can be converted into Maxima's language.
Answers in different units (which are dimensionally equivalent) can be compared (though author of question can limit this if required).