Why is the Aran class so unpopular?

I don't really know what "OP" means. Sorry. I'm still getting used to the speak. I know Aran can be hard to use but I've always liked the warrior class so I thought Aran would be my best bet.

It stands for overpowered. It's hard to compare classes, but since Aran has been out for a while and the newer classes tend to be very strong (before they are nerfed) and very flashy, players tend to gravitate towards the new classes rather than the older ones.