Just because the OP doesn’t want to explore every inch of Tyria with just one character doesn’t mean he is playing linearly, and it’s a valid criticism. I want to visit each area and explore as much as possible, but I want the experience spread out over multiple characters. When I create a character I’m always roleplaying slightly in the back of my head, and it has to make sense in my mind as to why they would suddenly go tramping off to another corner of the globe. It’s also about stretching the game out as long as possible, I don’t want to experience everything on just one character.
People seem to be having different experiences with levelling, some level really quickly and others level much slower. I’m getting there quite slowly, but it hasn’t been a problem for me. Either way I don’t think it’s fair to dismiss peoples concerns with levelling, as the game should cater the different play styles surely?