There's a lot of evidence that the next iPhone will have an incredible camera
A new, higher resolution camera may result in photos with even clearer, crisper detail, but megapixels aren't everything when it comes to cameras.
Rather, a 12 megapixel camera compared to the current iPhone 6's 8 megapixel shooter would allow you to record slow-motion videos in ultra-high 4K resolution. 4K resolution means video shot with the next iPhone will be about twice as sharp as video shot with the iPhone 6.
The iPhone 6 and 6 Plus both currently have 1 GB of RAM, which is your iPhone's short-term memory that lets you bring up recently used apps very quickly. There haven't been many complaints about the iPhone 6's performance, but it's possible Apple is just trying to future-proof the phone for software advancements in coming months and years.
More RAM would let your iPhone store more often-used apps in the background for you to re-open very quickly. But it could also have a small negative effect on battery life, as well as the next iPhone's price tag.
Still, these are just rumors, and Apple Insider also makes a point to mention that the source isn't proven. However, the alleged leak does back up previous rumors about the next iPhone. In fact, there were rumors as early as last fall saying the next iPhone will get a camera that rivals some "regular" digital cameras.
Other leaks of the purported iPhone 6S's design have appeared online, and there's also been mention of potentially faster 4G LTE performance, as well as better battery life.