Intelligent tutoring systems (ITS) have been a topic of great interest for about five decades. Over the years, ITS research has leveraged AI advancements, and has also helped push the boundaries of AI capabilities with grounded usage scenarios. Using ITSs along with classroom instruction to augment traditional teaching is a canonical example of how humans and machines can work together to solve problems that are otherwise overwhelming and non-scalable individually. The experiences of personalized learning created by (1) seamless orchestration of human decision-making at few critical points with (2) scalability of cognitive capabilities using AI systems can drive increased student engagement leading to improved learning outcomes. By considering two particular use-cases of early childhood learning and higher education, we discuss the challenges involved in designing these complex human-centric systems. These systems integrate technologies involving interactivity, dialog, automated question generation, and learning analytics.