Firstly, WP8 doesn't work with Zune, a dead giveaway that this is an old list from WP7 era. But yes, there's no support for Divx even in WP8. Most of issues on the list are so trivial, irrelevant or obscure (to me) I haven't even noticed after 1 month of use. As far as I can remember, 4, 7, 8, 9, 10, 11, 12, 16, 18, 20 are all false or at least partially false. The ones that are true are 1 (no quality loss if you use a good converter, plus who uses Xvid today? X264 works fine), 5 (you can swipe in to view it at any time, and it doesn't clutter when you don't need it) and 25 (although it does work as a USB Mass Storage device unlike WP7). The rest I don't know and don't care. By the way, also many many errors in the bigger list, some of which weren't even true for WP7.5!
PS: MKV container isn't supported by Xbox Music+Video, but MP4 works fine with X264. So a simple remux works with no conversions. For MKV might need a third party player. VLC is launching on WP8 soon.