They are likely to be facing similar problems, and it aids their networking. There are a number of reasons for challenging the received wisdom. They would expand their network better by joining standard courses with a varied range of participants attending. The only real argument for running a graduate only programme is to tackle the unique needs of this group. Operational, tactical and strategic modes - Identifying when to do a quick fix, when to plan, and when to challenge direction.
Graduates require a particular set of skills to become effective fast.
They have intelligence, confidence and 'attack' - the willingness to rise to a challenge. A prime focus of graduate training should be to practise skills in learning on the job. Graduates are good at learning in classrooms. They are not usually good at learning from colleagues, throwing themselves in at the deep end, or seeking feedback. All the learning they do on the programme should involve live experience, preferably on the job.