I seriously doubt that it's his bloodlines, more likely that he's just very green....sounds like very little in handling or training has been done for 5 years. So you have to consider him to be untrained at this point. Start from the beginning with his training. The fact that he is quite curious, friendly and unafraid in the pasture should tell you his true character. The thing about Arabians is that they are highly intelligent and very willing, IF handled correctly. You can't force them, or use force on them, or take shortcuts in their training. They will try their heart out for you if they understand what you want them to do. And they will be devoted to you for life. Sounds like 1. You need a trainer experienced in training Arabians, or 2. Start from the beginning with his training with ground work, lunging, round pen work to create a foundation and continue from there to create a foundation, and continue from there as if you are starting an untrained horse. If you can do this, I think you will be truly amazed at the jewel you have. Right now he's a diamond in the rough.
And since he's an Arabian, pictures are required......please?