Playlist - You should be able to have Playlists on your Channel, where you can set a specific Thumbnail vor this Playlist and use Keywords to automaticly add Videos to this Playlist. You should be able to give the Playlist rules like "Latest Video at top" etc.

Other Formats -
MOV
MPEG4
AVI
WMV
MPEGPS
FLV
3GPP
WebM
MKV (Matroska) is most important for me

Comment section - A Section under the Videos, where Users can Comment something. You should be able to even there let Moderators delete Comments. Should be the same Moderators like you have in your Livestreams.

Descriptions (better) - You should be able to set if you want to show the Description UNDER the Video, or at the Side of the Video (there where at Livestreams the Chat box is)

Monetization for Videos - Kinda self explaining ^^

Autoplay - A Autoplay feature which you as viewer can enable to automaticly get to the next Video of the Twitcher after the current Video, even should the "Twitcher" be able to make some "timecards" where they can link to a specific time of the Video or to the next Video, at the end of the Video. (Intro and Outro)