Actually Bluedog only assumes that he'll get a command within a year... What if his company decides to stop further expansion and postpones introducing new aircraft to the fleet or even cutback services (which is not so unlikely in the face of an economic downturn and rising fuel costs), his upgrade course may well be canceled and he'll be an f/o for way more than a year. In the same time, he could have gained hours and seniority on a 767 and be living the longhaul lifestyle (if thats what he wants). Of course it could all be different...
No matter how you take it, it's a gamble... So do you really want a change in lifestyle and scenery? Then go for the 767... But if you are considering the move only because your new aircraft is bigger and weighing twice as much as your current one, stay where you are and enjoy your privileges as a high seniority f/o and future captain