My personal opinion (and this comes mostly from researching on whether to continue) is that play with the new content. See how it suits you. There is so much content now, and more so if you want to build new characters, that it is going to pay off for a while (ONLY IN PVE) even if you are playing casually. When I started, I got a guardian and got it to lvl 80. Then I was farming for gold or dungeons or other stuff. Now, there is so much content, I started playing with my main character and created three more (ele, revenant, mesmer). I want to play around with them. And with the lvl 80 insta boost that I got from buying the expansions, I can try to see what my revenant can really do, without waiting for him to lvl up.