Some people just played a lot. Others used known exploits. A third group of players used the badly balanced apprentice system of Age of Conan to powerlevel, with reports that going from level 40 to 50 as apprentice takes 2 hours. As a result there are already a lot of level 80 players in Age of Conan, one week after release, 10 days after the early access started. And a huge number of level 60+ players as well, who'll reach level 80 next week. And then what?
I think leveling in Age of Conan is too fast. And of course its not good if there are exploits in the game that let you level even faster. I do like the idea of having apprentice / mentor systems in a game, but they should be balanced in a way to be not useable for powerleveling, they should just be a means for friends of different levels to play together.
If you reached the level cap in AoC in a week, you'll be bored of the game very quickly. That can be dangerous on PvP servers, as bored level 80 players are likely to gank others for entertainment. Of course the idea of getting to the level cap fast is to do the PvP endgame content there, battlekeeps and all. But if the game is buggy and exploitable, and people can insta-kill and shoot through walls, how much fun is PvP going to be? And for how long? Age of Conan might enjoy good sales due to its excellently timed release date, but I can't help the feeling that this isn't going to last very long.