343 is doing some really cool things with Halo 4 and this latest trailer shows off some of the features they have cooking. One thing I'm really liking are the Personal Ordnance drops in Infinity Slayer. Earning medals now rewards you, allowing you to call in a weapon or power-up item drop once you've accumulated enough medals/points.
The team at 343 are "still fine-tuning the system" according to 343's Community Manager, Jessica Shea. She goes on to say that players will average "1-2 ordnance [drops] per game," indicating that even highly skilled players won't be able to abuse the system.
I got two Personal Ordnance drops myself in one match when I went hands-on with Infinity Slayer back at E3. I think matches are just long enough that two should be the average for most players. Definitely check out Halo Waypoint's latest bulletin as they break down a lot of the new stuff shown in the trailer. November 6 can't come soon enough!