Shortcut,
I can assure you as a 'regular BKK-SYD' pilot that you are very unlikely to get one as its generally a very senior trip. However not impossible but as other posters have stated if you want the better trips be prepared to compromise on dates etc. Please don't be whining in 2 years time about lifestyle etc etc....!!! Its an awesome fleet and I have never heard even junior guys/girls complaining. A number of times I have completely forgotten to bid and have been assigned all the weekend supposed 'crap' but even then I have shrugged and enjoyed it.
The great thing about BA is the variety and all the Pilots have VASTLY different opinions about what is good for them. For personal reasons I love the East Coast USA and so am totally at odds with some of the opinions expressed here already.
Don't be blinkered or be cynical/jaded before you even join, try it all (you will get the chance) and form your own opinions of what you enjoy.
Welcome and good luck.
Toro.