1. Camera lens cover as an optional the other half (it's more hw)
2. Alien. Why? You build the app as a deb package (no packaging change needed) and just convert it to rpm.
3. libhildon, hildon (maemo5) qt style to be able to run native maemo5 apps!
4. phone speaker switcher (like on N900)
5. google drive, ubuntu one, dropbox
6. maybe support for extension in the web browser? adblock for sailfish would be great
7. encrypting the mail with gpg
/edit:
8. just type like in webos
9. personalizing gestures.

hw: it'd be great if they created an universal port in the other half stuff so that you can create any other half and just write drivers

plus fm transmitter!!

/edit2: a decent navigation suite like nokia drive or better
/edit3: plus a decent map suite like nokia maps or better
/edit4: more-infra: autobuilder/obs/whatever