I'm not sure what makes it easy but I know what makes it fun and that is its mobility and feeling of speed, at least to me. A rdm really pushing dps while they dodge mechanics with slidecasting and jumps is a thing to see. People do seem to have a hard time grasping the Dualcast mechanic for some reason, I've even seen it happen live while watching a family member try rdm for the first time and instantly floundering. But I think that all boils down to sitting down and reading your tooltips like with every other job in the game.