Quick reply (from Notifications) + Quick Actions API for developers
Dark theme (can replace default or in low light only)
Homescreen widgets (max 2x2 size in icon grid)
Silent Siri (type queries)
VoiceTime (HD FaceTime audio used automatically for calls like iMessage)
Scrapbook (replaces Notes, also launches for Mac, allows clipping of webpages and images as well text notes, Evernote rival)
Finder App (shows all files within apps on system, Open In facilities, tagging synced to OS X, remote access to Mac files)
AirDrop to Mac (send files to and from Macs as well as iOS devices)
iCloud Photos (view all your photos on all your devices with 50GB free space)
App-specific orientation lock (enable rotation on selected apps, i.e. Safari)
Security enabled apps (require fingerprint/passcode unlock for certain apps with sensitive data like Mail, Messages, developers can add to their own apps, optional)
Up Next in Music (brings the play queue from iTunes 11 to iOS, syncs queue across devices, auto mix using iTunes Radio)
Remote merged into Music (control Mac or iPad's music from your iPhone, switch playback between devices (i.e. "Continue playing here" on Mac from iPad)
Guest Mode (configurable guest mode which provides options for vanilla versions of apps like Safari, restricts access to apps like messages)
Camera and Photos improvements (line and circular depth of field in editor like Instagram, clarity slider, new filters, edits sync across all devices including OS X, brightness/contract sliders, photos and edits sync across devices, improved PhotoStream)
New Mail app (snooze Mail that needs action at some point, Junk Mail filtering)
Nagging Reminders (never forget to tick a reminder off again with an adjustable snooze option and persistent alerts for Reminders)
Natural language input in Calendar ("Lunch at 2 for an hour with Julie at McDonalds" and Calendar does the rest)
Self-destructing iMessages (direct swipe at Snapchat, iMessages can self-destruct after 3, 5 or 10 seconds if sender desires, users notified of screenshotting)
Would do me nicely.