Is it possible to have a busier tropical storm season in the eastern Pacific basin than in the western Pacific basin?
There are many determinants of tropical storms. The most important is to have sea surface temperatures of >27 deg C. Obviously, this will increase in extent, though not necessarily in frequency, with global warming, and increased incidence of El-Nino events. Shallow sea, as in the western Pacific, warms up faster than deep sea, as in the eastern Pacific. Hence there are always likely to be more tropical storms in the west Pacific. 
The second determinant is for the air mass to have a 'start-up' rotation, which is a function of latitude. That is, almost no tropical storms at the equator, but many in the tropics, as air masses pick up Coriolis rotation.