Well done non-defensive and great explanation of what happened and how it will be improved.

I would suggest that a continued effort be made to bring down the difficulty level.

The users who are the most impacted are mainstream users who have no idea why they have 4 sets of keys, and which ones to use. This is how I started too. My account and my wallet grew at about the same rate, so by the time security mattered it wasn't so daunting to understand the keys. Also consider making the KEY names more meaningful. APP keys (posting) and Wallet (active) Keys is one suggestion and would be easy to train. APP does anything but wallets actions. Wallet Keys are for all things wallet. The Owner Key should be "Permissions and Advanced Settings"

Just ideas to keep the site user friendly as well as secure.

Andy stated at one point your employees would be using the site. I see that as part of the problem. Those who are making the most important decisions are out of touch with the user base and the tools and have an inability to understand how changes will impact endusers.

People save their passwords here like anywhere else... that is a normal use case on MOST of the Internet.
If you sign up for a new site that requires "Training" just to login that is a large barrier to entry, and the double logins while maybe necessary and simple to many of you. Extra clicks, steps and page loads are usually a turn off to any end user.

I think sometimes you guys forget how much you know about crypto and you expect others to see it as simply as you do. For most mainstream users this is an entirely different experience. :)

Thanks for the update.