I agree with the QF argument - given the cosy relationship CX and QF have, there is little room for another asian carrier to fit in the middle. MH is not financially sound, nor do they have a management CX/QF/BA can trust. Thai on the otherhand has very strong ties to its founder SAS and extraordinary support from Lufthansa, just like Thailand and Germany have excellent business ties. That makes a oneworld approach very unlikely.

Don't forget that oneworld is essentially the union of BA and AA. BA+QF+CX+IB+FI are all linked beyond oneworld through investment, founding fathers, management ties etc. Any approval of another member means 'getting into the club' -- unlike star alliances which is just a loose network of opportunities to earn (increasingly diluted) miles. oneworld is an alliance depth, star one of breadth. Neither MH nor TG have the ressources (financial and managerial) to fit into the oneworld club).

My guess would be - for the next 5-10 years an expansion of CX and QF services around Asia, possibly the addition of KA and JL, LX if they don't go bankrupt again before. I don't see another member on the horizon.