I think that helped immerse people who didn't have the place on farm within the first month, because it struck a balance between trash making the place feel alive and getting to fight bosses frequently enough that you could fully enjoy them as lore figures (and Titan lore was a huge new area for them to open up with it, so perfect timing).
For all things immersive: Ulduar
For all things practical: Throne.
I'm also inclined to throw my vote in with Ulduar, but I'll vote ToT just because I can. It seems to be getting its due respect, but actually showing it doesn't hurt =P