The group i am running was lucky enough to have on eof the players pull the swordmaster class to play. While we only play once in a while we are about halfway to rank 2 and the group is starting to look at their next career advance. The only problem is where do you go from being the high elf elite i mean the sword masters are the guys that spend decades if not centuries to perfect their craft why would the player ever want to change from that career?

Don't interpret the career you advance into literally, my character is a gambler and has moved on to thief, though he is not stealing for a living and is very much still a gambler he has a more stealth focused approach to things.

Similarly a Sword master, could choose to focus on the basics (soldier) or put strength above finesse (thug) or vice-versa (thief)

Yeah, moving to soldier or mercenary to improve martial ability would be the most natural progression of swordmaster. Alternatively he could choose to broaden his skill base by doing something else for a while.

Also there is a good story to tell there as the sword master, a reclusive monkish warrior has to server his ideals as a soldier learning new skills that add to his survivability, its not a step down for him to become a soldier but more representative of the time hes spent in a company as part of a greater force. A good analogy would be the Jedi knights who during peace time are defenders of justice and basically a peacekeeping (super hero) police force (one very elite skill set) then the clone wars start and they have to learn to be soldiers and generals, same thing for the swordmaster.