It's crazy how editing still hasn't improved much on mobile. Compare it with the desktop editor. I guess people don't really do much editing on mobile?
The popup cards when you mouse over an internal link that they added semi-recently are an awesome addition, though. Great melding of the old interface with a highly useful newer feature, in my opinion.
Most importantly it hasnt adopted the Like/Follower count based Reward system that lot of people in the tech world have mindlessly included all over the place.
Try running any org with a Like and Follower count based reward system and check what surfaces and who pays a prices.
StackOverflow was doing good until the Eternal September began. They also forgot to take into account changing “best practices”
The main changes were the switch from UseModWiki to MediaWiki (using the Monobook skin), and from Monobook to Vector.