Repurpose of hi res sensor is most interesting, not just to take hi res pics(with detail repenting on processing) but to take low res sharp hdr stills and videos.
Not to forget the repurpose of Xbox depth sensing cameras for movements into safety one for iPhone.
I kind of wish the IR Blaster would make a comeback. With it on my LG V20, I can't tell you how many times it's saved my skin when a TV channel had to be changed or an app swap when the remote was nowhere to be found. I know it's on Huawei devices but I'm not using a network that supports their phones. Such a cheap piece needed for it to work; IDK why LG and Samsung removed it.