The problem with PowerPoint is that it incentivizes laziness and promotes pitch-culture to the detriment of quality in-depth discussion.
As I wrote in another post, how I would drive getting off of the pitch-train is through internal blogs, wikis, and possibly forums. The way things are today you tend to have 2 main tools in use: the pitch and then reactionary response (the email thread, bug trail, backlog, what-have-you). That's very limiting, myopic, and reactionary. It makes it difficult to have meaningful discussions at a meaty level of detail on things (designs, architectures, directions, etc.) Those things tend to happen in email threads which get unwieldy rather quickly.
You certainly don't need to have a report/document/memo/manifesto about every little thing. But when you need to have a discussion about, say, the direction of your whole product stack, major engineering changes, that sort of thing, it hurts when what should be a conversation at a level of an RFC is reduced to a pitch-deck that people then either thumbs up or thumbs down.
Today, I don't need an atlas of Georgia Counties. I've got Wikipedia and the US Census Bureau and free long distance on my cell-phone plan and minutes that go unused every month. If I have a question about Ubuntu, I don't need a manual. There's StackExchange and Google. There are lots of lightweight channels.
Don't get me wrong, I love books and deep knowledge. But the six months that it takes to produce, publish, and disseminate a tome doesn't offer slam dunk ROI. The agilists have a point.