Student Response Systems have long promised to enhance classroom engagement, yet adoption across higher education remains modest. To explore barriers to uptake, we interviewed teachers who have used such technology in their classes. Their experiences revealed three key challenges: steep learning curves, rigid constraints from pre-scripted quizzes, and disruptions to natural lecture flow. Drawing on Human-Computer Interaction principles, we translated these insights into design guidelines that emphasize learnability, flexibility, and minimal disruption. We developed a prototype Teacher Response System that enables students to signal confusion or pose questions anonymously, offering teachers low-friction, real-time feedback. This work positions a complementary approach that combines contrasting response systems to bridge structured student-centric interaction with dynamic, teacher-led responsiveness to support the situated practices of classroom teaching.