We've recently found out that the garrison will be heavily integrated into the leveling experience, requiring it to have a stable location (Frostfire Ridge for Horde, Shadowmoon Valley for Alliance) and that there will be specific racial-themed buildings for the professions section of your garrison. There's even going to be group content for garrisons. Mumper has even assured us that the garrison will not be required to level. Meanwhile, Muffinus has asked players who, out of the entire World of Warcraft, would they want as a follower - I'm personally pulling for Rexxar and Marhsall Windsor. Yes, I know.
What this all means is in flux, of course, as Mumper himself acknowledges - design is iterative, and changes happen. We're still waiting for more details, but what I wanted to talk about now is how the garrison is shaping up to become one of those rare things, a feature that can completely transform your playing experience in fundamental ways, yet not directly.