Meaningful and challenging psychiatry work is definitely not the domain of forensic psychiatry. You can find it in private practice, public, inpatient, addiction, child, etc. Many domains in psychiatry don't have 15 minute med checks. The length of follow-up appointments is not dictated by the field or government and many practices have 20 or 30 minute follow-ups.
Follow-ups are a necessary part of longitudinal care. If you want a field in psychiatry that doesn't focus so much on longitudinal care, you can look at inpatient, emergency, forensics, etc.
Forensic work is fascinating and you can learn more about it by doing a good search (use the Search link at the top of the page, select Advanced Search, then type "forensic" in the search box, check Titles only, and restrict it to Psychiatry). There have been a lot of threads that discuss what forensic psychiatrists do.
ADDENDUM:
Unicorn- You're really putting the cart before the horse here. In the past few weeks, you've started threads indicating an interest in Anesthesiology, Cardiology, Radiology, Pharmacy, Pathology, and PM&R, in addition to Psychology, Dentistry and Pharmacy. These are radically different fields and specialties. I'd suggest learning more about what kind of career you want for yourself before focusing on minutia like whether or not to subspecialize in something down the road. At the end of the day, the difference between a dentist, doctor, and pharmacist is a big choice. Once you decide doctor you need to decide on psychiatry vs. something else. Once you decide on psychiatry, you can consider forensics. Forensics is just an added skillset onto the foundation of well-practiced psychiatry.