We have some basic OpenGL effects (specified by the Effect and EffectType tables) which can be selected in HADesigner.
The one primitive that I do see that is missing is some sort of drag callback.
But come on guys, let's not let this be a "oh crap we don't have those features, so let's not do anything at all."
(1) HADesigners, come up with some stuff knowing our limitations, make the most of it!
(2) interested people wanting to hack orbiter, Hack orbiter to add the missing features!