I do not believe that PHL-SYD-KUL would be a legal DL routing. The obvious way is through NRT on DL, but partner airlines can provide additional options, all necessarily at low miles. Look at KE through ICN which has about five months of blackout dates every year, CZ through CAN, etc.

EDIT. Sorry, you said SWUs, not award tickets. SWUs can only be used for upgrades on DL and AF or KLM for Europe and TATL. Rather than nonstop from home to NRT, ask a DL phone agent to check for other international gateways to Asia, such as JFK-NRT, ATL-NRT, DTW-NRT, etc. LAX-HND is likely to be easy for award and upgrade space, but this requires an overnight and airport change in Tokyo.