Pretty sure you just said the same thing as quirel.
Limitations, of course, should eventually be required in order to realize a visual design that may be above and beyond output capability.

Concept artists shouldn't be limited in their vision.
Programmers know the hardware limitations and should pass those limitations on to whoever lies between concept and compiling, so as to best optimize the visual down that development cycle as a balance between esthetic, play experience, and technical capability.