Hapkido should never be used with grappling. This is because, the ultimate form of hapkido is to not touch the person with the palm of your hand. Now granted you dont even start learning how to do this until you have been training a decade.
Aikido is a much newer form of martial arts. This being stated, it is no less a martial art then any other. How great a martial art is depends on the person and the teacher.
If you come to a martial art wanting to learn how to smack someone around, then you can only learn so much. The physical aspect of any asian martial art is only half of the training. And no i'm not saying that martial arts is all about non-violence. Most martial arts in the world are about training for battle. However there is a great deal more to defeating someone then just getting them unconscious.
Any hapkido gym that doesn't throw their students is doing a grave injustice to their students. Also any martial arts gym that won't ever go full contact full speed and full power is doing a grave injustice to their students. However, don't think that in your first year of training you will be able to go full contact full speed and full power. I was training 3 years before I really started going full on. The reason for this is simple. Most americans are not in proper condition to take a punch to the head, have fingers broken in the middle of a fight and "deal with it," and most first and second year martial artists lack the control over their bodies to make sure they don't really hurt the other person.