Lots of people can get to the dragon, and anyone can wield it.
However, none of them can take it past the few rooms where you get it, as you are deemed not worthy, the area is no tele, no word, no commune, basically, there is no way to get it out but walk it, and the guardian always stops you, and if you kill it two more appear, and so on. I had a theory you could have phase wasp pick it up, leave, and command the wasp to rejoin, thereby passing it out to you.
Far as I know nobody has ever brought the dragon into Thera proper by being deemed worthy. Some people have thought having certain quests completed would do it, but none have worked so far. I couldn't do it even after having slain Tiamat and the 5 ancients, so it's not related to that.
It's an avg 33 nodisarm, exotic weapon, that is rot death, and progs dragon strength in combat, which also has very nice stats, and unfortunately attack type poisonous bite, it even has some old coding like immune to purging and I think shopkeeper inventory. I have the ID somewhere, but I'm sure it's been posted.
I could make any char have an eq freeze wielding the dragon, but that doesn't mean I got it out of the area.
Thieves have it especially easy in reaching the area, for reasons you can probably guess.
I feel like the amount of people that know the full path is far less, but I used to try and show it to people.
And really, there's not a lot to gain by going through the area.
I just liked getting the lost crown of dragonkings, because most people have never seen it.