I have been providing information through an in-game ticket.
My 2 cents is that they can't narrow down what's causing it - likely there are a few issues causing it, so they aren't getting a wide spread solution because there are different causes for different people.
I think it would help them immensely if they put in something that recorded app crashes. Then at least they would know what was causing it.
I have an iPhone 6 with the current iOS. I crash everywhere - when starting fights, when changing screens in a fight, when chatting, when just tapping to enter crypt. Usually there are subtle signs before a crash happens but sometimes it's just out of the blue. It affects me in crypt the most because those heroes disappear - it bothers me that the heroes are gone, but the attack count doesn't go up - that makes no sense to me.
Anyways - I am getting responses to my ticket and they are asking for additional information - which makes me think they are working on it. But I'm not feeling like a solution is going to happen today or tomorrow based on recent communication. I'm just happy the crashes aren't as constant for me as others have experienced.
Someone asked if others knew of any game as unstable as DS. I play quite a few games on my phone and a number of them have been unstable over the years. TsumTsum was unstable enough that apple mentioned it to me when I was having battery problems a few years ago. That being said, most are way more stable than DS.