I think it is a matter of luck too. I have three chapter 5 cities and I have obtained a second base in each one. I used the Ashen Phoenix in the oldest. The second city benefited from the 100 event currency I received in the mail. For the last one, however, I had to purchase 250 provisions to reach the same goal.
The only real RNG factor in this one is the maze generation. And even then, it's not nearly as brutal as during the 3 rotating chest style events, since you can simply ignore the more maze-like areas vs. wasting tools on them.
On the other hand, if you get 4, 5, 6+ awful chest rotations in a row, your whole event is basically blown up and you'll be completely screwed up for the rest of the event!
That happens to me pretty much every single event with the stupid rotating chest gak! Horrible RNG then means you become 100% reliant on either winning back an above average amount of bonus event currency (yeah right!), and/or you're forced to shell out dias to grab the 1-2 GP's the RNG screwed you out of.
Even worse when they attach a League competition to it all, since skill is all but non-existent in the 3 chest events, and it only matters how much sheer dumb luck you get and/or how many dias you can throw at things!
Call me old fashioned or "elitist" or whatever you want, but if competition is involved, then let me win or lose based on my own decisions and how much work & skill I put into it! I HATE losing to nothing more than a poorly programed, gak-awful RNG.
In this event, my secondary city ended 9 tablets short of the 2nd base building, mainly because I made a couple really stupid moves. (I was paying more attention to my kitty than the computer screen!
)
My main city spent 500 dias to top up the provisions, (really only needed about 25 more for a final big pack, but it was the final 8hrs or so), and easily made the 2nd Lv1 base building.
Both cities finished in Silver tier, with my main city being only 10 tablets out of Gold League! (in a 3 chest event, event with Ashen + constant daily collection, it still takes me on average at least 4k+ dias to attempt Gold league...)
Please give us more skill based mini games in League events - it makes the game far more enjoyable!