For its rollercoasters?
No, you shouldn't. It's not a characteristic of the city.
For its rivers?
Of course, you have to know about the four rivers.
For the Motepillo?
Definitely, you should try this dish.
For its national park?
Sure thing, when you visit Cuenca, you ought to visit El Cajas.
for the cathedral?
Yes, of coure. It's a must if you are in Cuenca.