Current the Math Formula Editor is hard coded to use OpenSymbol  and assigned variables FONTNAME_MATH and then as FNTNAME_MATH  and used as FNT_MATH 
There are a number of high quality font faces that have complete coverage of the Greek and Character Like symbols that the formula editor makes use in its specialized Symbols catalog, e.g. Cambria Math, Asana Math, STIX, etc. Any of which might be preferred by users as functional replacements to the bundled OpenSymbol font.
Suggest an ability in Expert Configuration dialog to change the font assigned to FONTNAME_MATH, or used as FNT_MATH would be useful. It might be grouped with the other org.openoffice.Office.Math StandardFormat stanzas.
This would be as an alternative to the general Tools -> Options -> Fonts: Replacement Table GUI where the replacement is global for all use of a font, OpenSymbol in this case. And if it proves popular, the ability to change the default font could later be added to the GUI settings panel for Math.
Definitions for the other Greek symbols %alpha... %gamma in the Formula Editor symbol catalog look to be defined in:
Glyphs refered to by decimal equivs of their Unicode codepoints, but since the .XCU has a hardcoded OpenSymbol font Name attribute set it may impact ability to have a simple attribute change set from Expert Configuration.
Just changing the font is not enough, may symbols are hardcoded to use PUA code points from OpenSymbol, so changing the font will give you garbage. This needs to be fixed first.
OK, so IIUC use of the font replacement table work because the glyph has already been selected and then the replacement can proceed?
Should the OpenSymbol font be reworked to eliminate any direct use of the PUA defined glyphs?
I'm not sure it's possible. To have correct display, glyph's size should be specifically chosen to be usable stretched, stacked etc. Also, we stretch characters where they should be composed of a number of parts to display OK (braces/parens, etc) - now stretching makes glyphs thin etc. Fixing this requires changing current composition of glyphs. And if we go this route, then substitute should have these glyph parts available at the same codepoints as well.
Sure, and bug 32362 suggests the formula editor must go this direction.
but doesn't all of this require we have the U+239B -> U+23B7 glyphs available to use? Not yet the case in OpenSymbol, but common in other symbol fonts.
Seems like we should dump any hard coded use of OpenSymbol's PUA glyphs, and use Unicode near term in preparation.
And once we move to using the appropriate Unicode glyps, doing proper OpenType Math table shaping seems advisable as in bug 103680.
Problem of the PUA assignment aside, an effort here to provide UI to be able to change the default font seems reasonable, and would survive any refactoring of the sm math internals.
My comment would be that it's essential that we be able to change the font of our formula, independent of this immediate issue with the font metrics of OpenSymbol. Agree with Stuart's comments about the need to move away from any/all hard-coded dependencies on a particular font. But in the interim -- switch to a well-behaved font instead!!
*** Bug 67152 has been marked as a duplicate of this bug. ***
*** Bug 111700 has been marked as a duplicate of this bug. ***
(In reply to V Stuart Foote from comment #5)
> Seems like we should dump any hard coded use of OpenSymbol's PUA glyphs, and
> use Unicode near term in preparation.
I suggest we can replace such hard coded PUA code points to Unicode equivalences firstly, and then create a converter to replace them when LO imported a formulae including such glyphs.