Lots of footage and talk about their motivations behind multiplayer. They're merging all modes - Campaign, Spartan Ops, War Games - under one persistent career and trying to make the game more accessible for a new audience. There will surely be some controversy over things like not being able to drop the flag, not getting unscoped while being shot, and of course all the new loadout customization options. It remains to be seen how base player modifications will affect gameplay balance on a competitive level, but I'm willing to give 343 a chance with their decisions because the game does look great overall.
Also looks like they're having playlists organized by specific gametype, perhaps to better hone skill-based matchmaking: