Like many things on Wikipedia, as the website grew, the anarchic fun of the early days started to fade away. Hence, we are starting in 2011, when things were still fun and chaotic. To wit: in 2009 (not even during April Fools' Day, but on a random day in August), a "LOLKeats" was made to explain a poem by John Keats, added to the article, and nominated as a featured picture candidate, with the claim that the articles it's in are "Ode on Indolence – Limited time offer". This wasn't considered disruptive, or worthy of a block: it was all harmless fun. Nowadays, I can't imagine it going over so well as the reversion text being merely "I have to admit I laughed, but lolcat go byebye:)".
I do think Wikipedia has lost some of its fun. That's not a good thing, but it was inevitable. Those early days were collaborative and wild with a heady sense of purpose. We were building the encyclopedia. You could take a famous figure and make them a featured article from very little. I don't think we can ever get those days fully back, and that's the nature of success.
Also, afraid we're going to need a part three. On the upside, this series can be linked to for years to come.