Prayer is played in the key of D# minor since the instruments are tuned down half a step. meaning that the key changes to F# minor on the last chorus. anyways, he never sings the 'living on a prayer' bit save for the line before the solo. meaning the highest note he's expected to hit is the one on the last chorus would be the one where he sings 'MY' on 'take MY hand', the usually flattens it live anyways.
What I fear is that they don't to the key change (for the last chorus) anymore thought that would be a MAJOR turn off so I doubt it'll happen. Let's face it, that's the climax of the song, especially live.

All this talk about key changes may mean one thing though: they might tune their instrument a WHOLE step down on certain songs. so prayer would be played in D minor and transposed to F minor on the last chorus. I doubt that would make it sound too different and hardly anyone would notice it. I've been blabbing about this for a long time. they should tune a whole step down on certain songs. plus, with all those guitars and basses and a dozen of roadies, they could swap instruments in no time.
That would be the ONLY reasonable thing for Jon to do. Prayer remains a big turn off in general for me when I saw them live and even when I watch the videos on youtube. It hasn't sounded decent in a decade. I liked how it sounded on the these days tour and even on the crush-OWL tours. and that was it.