In a blog post, yesterday, Microsoft outlined their Unified Update Platform (UUP) initiative. The short version of this story is that UUP, which is expected to affect consumers with the major update after the Windows 10 Creators Update, will shrink download sizes of updates by omitting portions that are already on your device. They claim that it is expected to result in about 35% less bandwidth used by a major update.
Beyond bandwidth, Microsoft also claims that this will help battery life and time spent searching for updates, because the difference is calculated in the cloud. (I guess you can call that reAzurement. I'll see myself out.) At least for mobile, I can see how this might be cheaper than the new system completely client-side. I wouldn't say the current method is too slow, though. I mean, it takes a while, especially a Windows 8.1 laptop I have at times, but I don't really see how it would help a gaming PC that likely has a faster processor than their servers.
Also, if you're the type of person who likes to scorch earth on a regular basis, I'm guessing Microsoft will still be providing ISOs that can either clean install or perform the typical update method. Also, this new feature will reduce the download size of cumulative updates, which are inherently very redundant, so that should be good.
I can't think of a real negative to this, especially not with the ISO workaround for the more picky power users. Maybe I'm not thinking of something, though, but it sounds like a net win (unless it turns out to be an unstable mess).