For an advanced student of computer science, I would say currying is a simple concept. I would even say that for a not-so-advanced student of computer science who has been made to sit through a couple Scheme-based classes, currying is not an advanced concept. But many CS students I have meet have been trained in either C/C++ or Java and for them the idea of currying is very foreign. In C/C++ to do it would surely be an advanced usage of the language (if it is even possible), and currying in Java is impossible (unless you are using the Pizza compiler, but thats not Java and certainly not for CS 101).
And lets not forget that many programmers didn't go to school for CS (me amoung them). I highly doubt you are going to find the topic of curried subroutines anywhere in a MIS cirriculum, nor are you likely to find it in an Elec. Eng. progam. Many a EE and MIS grad go on to be programmers/developers. IMO functional programming in general is still a largely acedemic CS territory. Although as time goes by I am seeing what I would describe as a slow-leak of functional thought into the mainstream (OO/procedural) programming world, which I think is a very good thing.
As for how curry-able old crufty perl subroutines are. The more I thought about it, the more I think I put my foot in my mouth there. There are of course some odd cases where things will go awry, but thinking of modules like Memoize (which in many ways does things similar to currying) I can see that it would likely work out better than I initally thought.