Good questions! The unit I work on gets HIV patients, and they are on a slew of meds that should require more specialized care from the staff treating them than just "generic care". I liken the care of an HIV/AIDS patient to a specialty like Cardiac, Pulmonary, CCU, Renal, Neuro, etc.
It would certainly help the patients afflicted with this illness to receive more specialized care from staff who were more familiar with the progression of their disease process, the medications and side affects of those meds, and the emotional/mental depression associated with a disease process that will require more intervention from a "lifestyle change" method of treatment for those patients.
I've worked with many HIV and AIDS patients in my nursing career, and I could easily see that focus of nursing as a specialty. The care they need requires more than one can possibly imagine.