I decided to switch to Lucida OpenType, but now I’ve another problem. In the Type1 variant, all geometric shapes (\square, \triangleright, \blacktriangleright, etc.) had the same size as math operators (\boxplus, \boxdot). This appears not to be the case any more in the OpenType variant, they are way too big! (See attachment.) Pagella and Latin Modern do this right. 

Is this a font issue or a ConTeXt issue? Anything I can do about this without redefining every symbol I need by hand?

Cheers,

Tim