Mine is a 2013, and it's My Ford Touch. The app interface apparently only ever worked on the earlier Sync system -- it showed up on the menu of MFT, but it was apparently never implemented, probably for the reason you mention.
The MFT menu system seems fine to me, other than functions that kept getting removed with each new version, apparently in an effort to trim the system down enough to be stable on the limited hardware. It will change time zones if you drive over a time zone boundary, yet you can't select Daylight Savings Time. Etc.
You're right that the nav system is pretty bad. The display is actually nicely thought out, but it tends to get confused a lot, and the POI database is minuscule. The only vehicle-moving crashes of the system I've had were related to trying to use navigation at the same time as playing music. Too much for it to handle, leading to a five to ten minute freeze followed by a reboot. After a couple tries like that, I simply stick the phone into a holder and use Waze.
My speaker phone performance hasn't been a problem. I've only used the voice commands to make phone calls, and they work pretty well.
I don't use voice commands for music, since I just put it on random play and never mess with it. So with music and nav out of consideration, I don't know why I would ever actually use the voice prompts, even if they worked perfectly.
The music system would be great, if it actually worked reliably. When it's working, it's doing just what I want, with a pretty good interface.