I don't think it can happen because of 2 reasons.
1.Richie and Jon are still ''at war''.
2.Just as someone mentioned above,Jon can't even sing WAN,BWC properly...so I can't imagine him singing stuff like Does Anybody Really Fall in Love Anymore (it would probably sound like ''di anyoni ily fall in love anyooaaa'') or Backdoor To Heaven,House of Fire etc.
Seriously though,if Jon doesn't take care of his voice,around 2018 his setlist will consist of 3 hours of just shouting ''iiiiiiiiiii'' as nasally as possible and maybe if we're lucky we'll get an encore where he will whisper Lost Highway or WWBTF.