Too early to start thinking about iOS 9? Not at all. Features are already getting pushed, pitched and locked down for next year, so what better time to bring some attention to things that... well... need some attention.
"Hey Siri!" is a good one to start with. When your iPhone or iPad is plugged in, and "Hey Siri" is enabled in Settings, you can activate voice control simply by saying those magic words. The problem is, everyone knows those words and every plugged-in iOS 8 device recognizes them. That leads to inopportune activations — mischievous and accidental alike. How could "Hey Siri" be improved?
Google's "Okay Google Now" tries to learn your voice; if it hears someone else yell the activation phrase, it hopefully ignores it. That's an okay alternative if you're the only one who ever activates your device, you never get a stuffy nose or sore throat, or Kevin Spacey never manages to adequately imitate you. But if you do want your significant other, kids, or other friends or family members to be able to activate your iPhone or iPad, you'll still want magic words to work universally. You might just want different magic words.
If you've ever listened helplessly as an obnoxious podcast host yelled "Hey Siri"; yelled "Hey, seriously?!"; or even legitimately said "Hey Siri" only to have multiple iOS devices respond, you've probably wished for a way to customize Siri's magic words. "Okay Siri," "Yo Siri," "Open Siri Me," "My voice is my passport," "Tea, Earl Grey, Hot," — anything! The ability to set an alternative short phrase to activate Siri would make that feature much, much better.
Perhaps a "Customize 'Hey Siri!'" button could be added to Settings. Tap on it. Say your customized activation phrase. Have Siri show it to you as text and ask you to repeat it again for confirmation. Approve it. And you're good to "Go, go, Siri gadget go!"
If for some reason a purely customizable phrase isn't technologically viable — though given Siri's ability to call users by a custom nickname, it certainly seems in the realm of possibility — I'd settle for at least a half-dozen or so built-in options.
Whether or not Apple ever adds a Moto X-style always-listening coprocessor to the mix (allowing Siri to be voice-activated even when not plugged in), adding the ability to customize or change your activation phrase would help prevent obnoxious podcast hosts, mischief makers, accidental word collisions, and wrong device activations. It'll just work better.