I think voice has nothing to do with it. Most (not all) of the songs on These Days aren't really the big, fun, concert songs Bon Jovi are known for doing. Also, I doubt there's a lot of band-audience interaction that can take place while performing them. These aren't exactly sing-alongs, here.
Still I wonder why they didn't do Someting for the Pain. That's as fun and catchy as These Days gets and it would certainly do well at concerts. It's also one of the few songs on the album that's not sad (note I wrote SAD, not BAD). It's a shame they haven't performed it on this tour, yet.