A little common sense would go a long way here. The tour is not going to flop and at the same time it will not sell out every venue. Athens will not be a sold out and Romania will not be a friends and family gig.
Will the tour overperform? Probably not.
Will the tour underperform? Maybe, but definitely not a flop.
Did they overestimate the potential? Maybe yes, maybe not, we'll see. It's possible that they booked stadiums expecting to fill a 70% capacity because there were no other venues available at these specific cities with that kind of capacity.
Did ticket prices play a part? Absolutely. Especially considering it's the first time Maiden have really let down a lot of people with ticket prices.
But in the end tour will be a success.
And if we are lucky they'll go back to touring arenas next time, where the production they have belongs.