Adding four random digits to people's names was a brilliant solution to two common problems with usernames (users wanting the same username and usernames of notable personalities getting leaked), and now they're just going to the exact same system everyone else uses with all of its attendant problems? Fuck off
Removing the ability to sort from old to new means that you're on the page looking for stuff longer, are more likely to get distracted, and spend more time on their site, which increases revenue. It's a no-brainer for them