Different people have different playstyles (and yes, I do have a Watchtower). I don't like population/culture buildings because they're hard to work with long-term. When you first get them, they're great, but then they become obsolete, and you have to either get equally lucky with the next event, or you have to do terrible drastic things to your city. I made that mistake with the last winter event, and my city was crippled for months as a result. I'm not going there again. One or two of them is fine; not more. Obviously you're better at working with this than I am, but not everyone is. A lot of people have trouble parting with event buildings, for nostalgic reasons.
I'm actually in favour, in general, of the new variety of building types offered in events. More variety is good. But this event had, what, two buildings that just gave high culture? One of which came out very early, when a lot of people aren't going to spend nuts yet? And now they've changed the other. After Woodelves, buildings tend to either give high culture or they give mana, and there's a balance. The event buildings need a balance too. Smaller cities, in particular, do not want all of their options to give supplies -- it's great that they decided to accommodate more advanced players with event buildings, but it's not as great when all of the buildings are like this.
If I had been inclined to spend diamonds on an event (and I wasn't, but I could have been), I definitely would not do it now that we've learned that the same prizes we spent diamonds to get can be changed retroactively into something we might not want.