Sandbox is the biggest complaint I have. I can understand it with the iOS to some degree. At least there they are constantly providing new features and hardware changes to help apps keep being innovative.
An issue that takes you 3 minutes to fix and re-upload. And then you need to wait another 7 days. (If you're unlucky they find something else for 7 days more of waiting time).
In fact, all of these points were made directly in the article, which I'm not certain you read:
App Review continues to take at least a week...
there are technical limitations imposed by the Mac App Store guidelines (sandboxing and so on) that limit some of the features we want to bring to Sketch,...
Most likely not.
Check out the myriad of issues with the MAS on HackerNews: https://news.ycombinator.com/item?id=10655853
In fact, all of these points were made directly in the article, which I'm not certain you read: