Every alliance needs a balance of big intercontinental carriers and smaller regional carriers. This is exactly what Malev, Royal Jordanian, Dragonair, LAN Ecuador and LAN Argentina are doing for Oneworld.
Many smaller airlines in Star like BMI, LOT, TAP, Spanair, Shanghai Airlines and US Airways aren't very well known outside of their home continents but that would not conjecture that they are as useless to Star as Malev and Royal Jordanian will be for Oneworld.
Also, since when did Qantas hint at leaving Oneworld or own a majority stake in Air New Zealand? I thought the NZ government owned 79.9% of it. Qantas's interests in Air New Zealand are only in the form of convertable notes to the amount of about 0.4% of all of Air New Zealand's available shares.