It'll be interesting if they do come back from a year "away" to spend the best part of 2017 promoting a 30 year old album and holding off on SOE til after the summer.
Not exactly suicide, especially if they drip feed new singles through the year, but a bit of a gamble in terms of cementing some people's view of them as a "heritage act", literally reliving former glories. But it will probably pay off!
Best case scenario, in my opinion, would be
-SOE in March (9th/10th?)
-restarting the IE tour in arenas in the spring (if that rumour's true), few more JT songs than usual, especially during the screen/e-stage segment.
-separate Joshua Tree anniversary stadium gigs in the summer
they could basically have their cake and eat it this way. They don't have to spend a year looking backwards when their new album's sat waiting to be released, and get to celebrate one of their best albums with the added bonus of keeping livenation happy.
very unlikely though.
and like ChargedVT's said, probably no chance of them ending up in Australia. These guys really do get screwed over each time. I bet anything all UK gigs are right before I return, so I don't know why I'm even getting involved in the discussion.