I thought I'd see if I could strip out the redundant #includes, so wrote a little script to remove each one in turn from a file and ascertain whether the thing would still compile. It's a bit slow but the results for mathed are promising.
Angus command_inset.C before: 85, after: 85 formulabase.C before: 973, after: 959 formula.C before: 336, after: 320 formulamacro.C before: 187, after: 177 math_amsarrayinset.C before: 104, after: 102 math_arrayinset.C before: 132, after: 131 math_atom.C before: 50, after: 48 math_autocorrect.C before: 184, after: 181 [snip...] total #includes stripped out: 168.
strip_includes.sh
Description: application/shellscript
stripped_includes.diff.gz
Description: GNU Zip compressed data
