They are on-demand services rather than linear channels, but I would like to see Netflix and the upcoming WWE Network (supposedly launching in three days) on YouView.
Netflix seems like a no-brainer given how YV declares itself the No.1 platform for non-satellite on-demand viewing. But for whatever reason YV and Netflix can't or won't come to an agreement, even though you can receive it on TiVo and a lot of Freeview+ boxes now.
As for WWE Network, I tweeted YV and asked if they'd be carrying this in the future. They said something along the lines of that they're always looking to add additional content and to watch this space. But I suspect they may have just been giving me a bit of friendly flannel!
The only linear channels I'd really like to see on there are Sky One and Sky Arts 1 & 2. But this is pretty unlikely, at least for the moment as Sky see BT as a massive rival and don't want BT's YouView platform carrying their channels, as evidenced in the ongoing Sky Sports wholesale debacle. Sky Sports News HQ would be a good addition too.
Ironically my brother, who lives in a different flat in the same building as me, has Talk Talk YV and gets Sky One, Arts and Sports News in the basic TV package. But he isn't bothered about One and the Arts channels, only Sports News. Whereas he is envious that I get Crime & Investigation in my basic BT package. He could get that channel too, but like me, he doesn't want to pay extra to upgrade his package. I'd consider paying a little more for a few extra like the ones above (if by some miracle BT and Sky can end their standoff) but overall I think BT are currently providing a decent selection in their basic package; I enjoy Gold, CI and Alibi in particular (and BT Sport, though that's free for anyone getting their broadband with BT, obviously)
One more thing: I LOVE the BT YouView recorder. It looks cool, matching the BT router that sits nearby, decent remote, and is easy to use with very few lags and blips. My brothers Talk Talk box, on the other hand, the remote seems poorly laid-out by comparison. He's been a YouView user about a year longer than me though, so I don't know if TT have brought out a new, better box like BT did not that long before I signed up with them.