Is it really possible to plan a degree?

Yes,......and no. Course offerings at the upper class and graduate levels depend on the availability of faculty and also on enrollment. Faculty go on leave and courses get canceled because of low enrollment.

... but I saw all those wonderful courses in the catalog ...

Of course you did. Hundreds of courses are listed in the University catalog. Many, many of them haven't been taught in the last 5 years and others are taught so infrequently it is impossible to plan on them.

Never, ever assume that just because a course is in the catalog that you can take it.

So how do I find out what courses actually get taught?

For Asian Studies students: Use the planning tools offered by Asian Studies. They are not perfect, but they can help.

For non-Asian Studies students: switch to Asian Studies!