I would be very surprised. Apple has tried hard to have standard apps that are always standard apps. Intents give you choices for your standard apps which give you (even if minor) fragmentation. That is something people see differently and for me personally that sounds like hell. But to each his own and I'd even guess people with no technical knowledge might prefer not to be bothered by such choices.
I love Android intents and can't wait for webintents to take off but I can't see Apple embracing intents or something similar on iOS.
I'd say if Apple opens up that sort of customizability, it'll have strict requirements around the interface/behavior and, if those requirements change, 3rd party apps will have to change rapidly with them or be rejected from the Store. In other words, their control over the Store could allow them some flexibility to allow some customization in ways that avoid fragmentation.
I love Android intents and can't wait for webintents to take off but I can't see Apple embracing intents or something similar on iOS.