SQ is good but it isn't that good. There are plenty of truly great, special first class option in Star Alliance:

Swiss new first on the A330-300 (eg JFK-ZRH, ZRH-DXB)

Thai Airways first -- not the onboard product as much as the Bangkok departure experience (very personalized and an absolutely lovely spa)

Turkish first on the 77W (but beware aircraft swaps). JFK-IST, IST-BKK/HKG/NRT? Not daily service with 77W usually, avoid the 2-cabin Airbus. Great ground service and suites.

ANA first class, IMHO best food in the sky. ORD-NRT is pretty available in Dec/Jan/Feb/Mar.

Lufthansa first -- OK the product isn't great but if you haven't visited the First Class Terminal... (which you could do flying FRA-ZRH connecting to Swiss first )

Asiana first... ICN-JFK is pretty available as is ICN-ORD, but ICN-LAX availability is AMAZING. Great food and service.

And don't forget all the short-haul F around Asia eg ICN-PVG on OZ, PVG (and PEK, NRT, HKG)-BKK on TG... BKK-SGN on LH, HKG-SGN on UA, etc etc.

Honestly the things you can do with 120k Aeroplan miles (forget RTW!) are AMAZING considering you can cross both the Atlantic AND the Pacific and book two stopovers. Then just embed a few side trips...