Same as it took Apple 7 iterations of iOS to give us a Control Center Android has had since its inception, it's probably going to take them a certain number of years to add one lousy, tiny single-color blinking LED near or inside the earpiece in an upcoming generation of iPhone.
Said LED that you'll have to wait another couple years until it actually blinks in different colors, depending on what notification it's supposed to convey...
I agree with helenjane: Apple does that on purpose, to keep us tethered to our iPhones, and it's kind of pathetic, really, especially coming from a company that's sitting on a pile of cash so huge it doesn't know what to do with it. There's no technical explanation to support their refusal to add this tiny feature to recent iPhones, so basically, it boils down to marketing moves.
Jailbreaking your devices won't really help, because I don't know of a tweak that does what we're asking for here, not even one that could emulate what the NoLED app does in Android.
My next smartphone could really be that: smart. I imagine it won't embark iOS, though...