He should, but he won't. He's got a great voice, but it's not really needed. Bon Jovi were a great 5 piece band until 2004, so we know he isn't absolutely necessary (except on a few songs like WWWB or WLOL, which we could do without).

I'm fine with him if he was a rhythm guitarist. The thing is, you can NEVER hear him, except when he's butchering a solo. I couldn't tell you what Bobby plays on half of the songs. He's not an official member, so he shouldn't get any solos. If anything, Dave ought to get more solos.