I was usually put off by Multi View Demos in CPMA, but I think that was mainly because it screwed up the sounds -- you could hear both players' sounds instead of the POV.
The last one could definitely work in my opinion, but I think the same could be achieved if the casters just give information on where the other player is.
It is great to have player games, especially on the individual players.
However, when they are small we can hardly see them as they are pretty far away + if people have twitch on low settings it will be very hard to see them.
I like the halo cam but the cams are too big and you would have difficulties seeing the game play, especially with quake also because people want to see the chat, like myself!!
Last suggestion looks great (maybe the PiP needs to be a bit larger, especially for people streaming lower than high/source). I think you can change the location of chat (cfg or hud or whatever?), just move it up a bit so it's right above the cams?
first and last are great, wouldn't care if it was one or the other, though the last one might be a little too much. i think someone should experiment with the spectator hud, change things around. i don't like the bar at the bottom of the screen and the score boxes are kind of big.