Amount of responsibility given.
Lack of formal internship program and training.
Advice to Potential Interns
You have to be proactive about asking for projects and more responsibility, do not be afraid to speak up and be open about your skills. If you ask, you will be given the work, if you do not you will sit on your computer doing nothing.
Advice to Management
More formal training process and connections to new hires around the nation, interns convention or the sorts.