What? Have they not added all that in the year since release? That is about normal for most MMOs. Rift and GW2 are about the only MMOs that went content crazy after release. WoW added quite a bit in the first year too. But ESO has been fairly consistent with many MMOs. Wildstar has released less content. I don't remember a ton of new stuff released in the first year of Age of Conan or Star Wars, though I didn't play SWs really so I could be wrong.
ESO has added bigger delves, a dye system, Trials, the Justice System, the Champion System, improved animations and Craglorn. Of course, I have not been playing the entire year so most of it is new to me. I will see how they do for the next few months and go from there.