OK, just for the heck of it I decided to go to my 12 cities and list from oldest to youngest just where I finished in this event as far as the main prize is concerned. I don't actually have the building placed in every one of my cities - don't have the room in a couple but if I find I need the T2 goods, may put it up later.
So from oldest to youngest, by chapter (not world):
1: Chapter 12 - Level 5
2: Chapter 12 - Level 6
3: Chapter 12 - Level 9
4: Chapter 12 - Level 10
5: Chapter 12 - Level 9
6: Chapter 11 - Level 9
7: Chapter 10 - Level 8
8: Chapter 9 - Level 9
9: Chapter 9 - Level 8
10: Chapter 6 - Level 10
11: Chapter 4 - Level 7
12: Chapter 4 - Level 6
Not sure what this says since I worked just as hard at the event in all of the cities yet my oldest and most advanced city did the worst and I only made it to level 5 yet it's random enough that both another chapter 12 city and a city that's only in chapter 6 both managed to get as far as level 10 with the Gingerbread Mansion. Both the two oldest and the two newest of my cities did the worst which shows that it was a difficult event (at least for me) in the newer and older cities because of the type of quests I got in those cities. (too many VV or complete a research or scout in the large cities and too many gain goods, buy KP or deal with the wholesaler in the small cities) Far too many cities where I didn't make it any further than level 8. I spoke before of player expectations and how, even if they aren't reasonable expectations, they are nonetheless human nature. My expectation with an Event like this is that I should have a good chance of my cities - all of them - being able to make it at least to level 9 with a majority of them being able to upgrade the main building completely. Maybe that isn't reasonable to some people but it is what I expect of an event that I enjoy. The idea that Inno doesn't want to have people having more than 1 of the main event building is something that is very easily addressed without making it ridiculously hard to make it to at least level 9. It's been said before by many here: if you don't want us to have more than 1 of the building simply don't offer it more than once! Give us a good/fair chance to get a fully evolved building but don't make it possible to get a second!!!
The mechanics for this already exists. It already is in play where the magic chessboard is concerned. Just use it for the special Event buildings too!
As for the event as a whole, I did not enjoy it as I have other events. Random quests that are anything but random (I don't care what wording you use - getting 5 quests in a row to gain or make supplies is not random!) are boring beyond belief! The whole having no choice on how much of the event currency we spend and having no strategy for what box we pick was tedious. I much prefer being able to choose how much to spend on one of three "boxes" depending on the percentage of chance I have of getting something I might actually want. The whole setup used in this event was badly flawed and the 2x and magnifying glass ones were worthless. I actually am one of the few that didn't mind the shuffle one... I saw it as a bonus hammer since we got the 50 ribbons back and I actually was fairly good at figuring where the best items were based on the type of box. (even though the best changed type of box each time, I was still lucky with my guesses...) If the next Event is based on this style, rather than on the rotating 3 prizes like in the past, I will be much less likely to work very hard at it, if I bother at all. Boring, tedious and basically annoying... that pretty much sums this event up for me.