The term "pitch class" is so useful. I even think it's helpful with students that have no musical background. But is that just me being stubborn? Uncomfortable to use terms like pitch and note when defining scales, etc? Is it alienating jargon? Alienating jargon is common to most specializations, but "pitch class" seems necessary and not so difficult to explain.
A term I could do without is "tritone substitution." This sounds very heavy and complex, but is actually a very simple concept. I wish there was a better way to say it.