I don't get why the 5 min mark. Some matches can be resolved at the 3-4 minute mark easily and should definitely be considered as legitimate.
Presumably to stop you grinding the AI.
Anyhow, none of what they said really explains the system or the plans they have for it. All it said is that "War Spoils drop randomly when you play games", which if people hadn't figured that out by now, I'd be worried for them. The only bit that we could've guessed and didn't know for certain was how the length of the game effected it(Which is a function I don't see the point of).
Hopefully they have something bigger planned for War Spoils, a system like this has so much potential and I don't want to see it wasted.