McGill has a very large campus, student body-wise, but a relatively small campus facility-wise. Almost all of the buildings circle around a good-sized quad, which makes going from class to class much easier and helps the large school feel much smaller. This setup, however, limits the amount of buildings and venues the campus can fit. The gym is pretty small considering the student body numbers exceeds 20,000. The William Shatner Student Centre, besides being humorously named after our Star Trek alum, is the only student center on campus, and is the headquarters of the SSMU (Student Society of McGill University). Clubs have most of their offices in this building, and right next door are services, such as the health clinic and financial aid office. On the first and second floors, there is a not half-bad food court and study lounge that is very popular with students living off campus in between their classes. The basement houses Gert's pub, the only on-campus bar, and the organic food co-op.
The thing is, one of the main reasons why McGill doesn't have that many services is that it doesn't need to. After first year, everybody moves off campus. What McGill does not have you can surely find in the neighborhoods surrounding it. There are tons of coffeeshops, convenience stores, and restaurants offering cheap lunch specials and student discounts. Like most universities that are located in the heart of large cities, the city picks up the slack for whatever is lacking in the school. More facilities would definitely be an improvement on the campus, but expanding downtown is probably not feasible, and not really necessary, given all that the city has to offer.