Those of us paying attention to the snapshots Mojang have been releasing in the run up to the release of Minecraft 1.8 might have long since noticed a pattern to the additions to the game, an awful lot of it is centring around making building maps of different types easier to automate. Most of this seems to be because the way blocks are rendered among other things are being subtly fiddled with 'behind-the-scenes' in the run up to the implementation of the plugin API that Dinnerbone has been promising for a while, meaning a lack of 'survival' changes to the game.
Snapshot 14w07a is no different, although it does bring new iron trapdoors to the survival aspect of the game. Otherwise the majority of changes in this 'smaller snapshot' (Mojang's words) centre once again around adding new ways to customise and set-up maps and mini-games for map-makers to use.
The two major map-making additions in my opinion are the ability to now display team objectives that can only be seen by the team it is for (filtered out by 'team colour') and the ability to at last switch off nameplates above a player's head, using the teams function. That last one especially will have a major effect on Survival Game type maps equal almost to how Spectator Mode did back in snapshot 14w05a.
Other notable command additions have to do with the /scoreboard command added in the last patch, with some new subcommands /scoreboard operation and /scoreboard test, operation used for math-based functions such as totalling up all the kills from one team into one single score and test used to make sure that scores are falling between set parameters (e.g. not under 0 and not over 100).
Needless to say, 1.8 looks like it's going to be a very good update for all map-makers in the Minecraft community.
Snapshot notes are here.