For me, I'll need a little more than a fingerprint sensor and some colors. I have a feeling that'll pretty much be the only difference though. Apple is too cheap/greedy to have a 128gb option but I could be wrong.
Way to think outside the box. You should probably go and have a little sit down now.
On topic - for me, I'd be coming back from Android. If the notification light is a reality, it's getting close. Wifi/bluetooth toggles and the ability to drag and drop (ie, no iTunes) would be necessary, too). In my opinion, the hardware for almost all phones is beyond what I need, it's the software and useability that I look for.