Thai have only 4 refitted 747's in the current fleet which may see long haul (Europe) scheduling again in the future. It's also possible they could be sold ahead of other out-dated models currently in storage and definitely for sale. The biggest impediment to TG's rehab process is the off-loading of the old and unwanted models in their grounded fleet.
As to flying Thai, up 2 you. Despite their excellent safety record and 1st class (home-based) maintenance division, I am not keen on flying with them again for several reasons. The potential for cancellation/loss of paid fare is high, as is poor service thru cut backs and lack of staff morale. TG may lose it's best staff, pilots and cabin crew included, to other carriers as WW air transport increases demand.
Singapore Airlines will be my preferred carrier to/from Australia. Thai AirAsia, well funded, will continue to be a favourite and if ever AirAsiaX resumes long haul I would book with them. For Europe, I'd choose Turkish Airlines for superb service or a ME carrier; Qatar, Etihad or Emirates.