This is the reason I got 7 (actually 9 but two were put on hold when my month's subscription ended) character slots. This way I have one character of every class with all their traits / swift travel / gold cap / etc unlocked. As someone else pointed out, the 70 quid I spent means that I am almost as well off as those lucky few who bought a lifetime subscription at that price. As I plan on playing on and off for at least a year (and probably a lot longer), this works out much cheaper than buying a subscription and I will own the content rather than losing access to quest packs when the subscription runs out....
My understanding of what your saying is.....get the subscription, create as many chars as you might want to use and then once the subscription runs out I will still have access to the traits and so on? then just buy the quest packs.