There is no problem in using whatever new devices you want,just so long as you have a basic idea of the ancestry of the new devices and why they work the way they do.Personnally I would be very reluctant to let a student jump straight into designing their own devices without any idea of how 'old'stuff works.

In that line, I would have my students (if I had time to let them fool around) design using discrete 74.. logic. This would, by far, give a better understanding than just inserting a 8255.

Erik