Update: Apple has finally switched currency in the App Store, Apple Music and the iTunes Store. The good news is that Apple is using a fixed price system with a lower exchange rate for all items. For example, a US$0.99 app is now only RM3.90.
However, the prices are not necessarily pegged to a particular exchange rate – for example, a movie like Jason Bourne is US$14.99 in the US iTunes Store but sells in the Malaysian iTunes Store for RM54.90 (which is about a 4.25 exchange rate) while renting the same movie costs US$5.99 to rent but costs only RM12.90 in the Malaysian iTunes Store (which is only using an exchange rate of 2.15 if you're counting). Generally, we've found that with the conversion to ringgit in the Malaysian store, we're all paying much less for our apps, music and movies. Yay!