Answer by Larry Summers:
Introductory economics has not changed enormously over the years. In part this is because much of introductory economics is established knowlege that does not evolve very much. For example, supply and demand, marginal analysis, and the quantity of money have not changed much. As with basic physics or calculus, introductory courses do not bring students up to the frontier of economics and so do not change that much.
This is reinforced by inertia among teachers of intro economics, and the tendency of popular textbooks not to change too much. And most economists believe in the basic micro/macro divide pioneered by Samuelson.
Main changes that have taken place track changes in economic thinking and in the economy. At least until recently courses have become less and less Keynesian with topics like the multiplier getting less attention than they would have a generation ago. More emphasis on economic growth and less on cyclical fluctuations. There has also been more recognition, though not a lot, at the introductory level of the importance of information asymmetries.
Other changes reflect a changing economy. Much more international stuff. More about China. Less about planned economies. More about finance and how it interacts with the economy. More about the long run costs of budget deficits.
Style has changed relatively little as best I can judge. Obviously some use of computers as devices for testing, exemplifying and illustrating. But in general universities have been surprisingly undynamic. The large podium small chair method continues to be main method of pedagogy.