> Having all these easily accessible on the outside of the building (instead of having to open up walls or floors) sounds like it should make maintenance easier

> Having all these easily accessible on the outside of the building (instead of having to open up walls or floors) sounds like it should make maintenance easier, not harder. Accessibility is improved, but lifespan is sacrificed. When the systems are on the outside they're subjected to much greater swings in environment (humidity, pressure, temperature, thermal expansion, and so on) that don't happen when they're inside the climate-control envelope of the building.