8k on modern engines with modern oil (yes even dino) is not extreme. there are many vehicles that call for 4-15k miles between oil changes. our jetta calls for 10k oil change intervals and yes thats with standard dino oil.
8k is very respectable and doable. what it boils down to is several factors: quality of oil you use, type of riding you do, and how hard you are on the oil (i.e. many short frequent trips, constant dusty conditions, extreme low temps, etc etc) and those factors call for shorter oil change intervals.
i do not go by mileage when it comes to changing the oil in the 919, i go by feel. when the transmission starts to get sloppy, it's time to change out the oil. this can range anywhere from 3k -5k miles depending on the season/riding conditions.