So I just did a quick scan of the North American shows. Most of the shows are pretty much sold out. Sure, some shows like MSG have some upper level $300s that aren't moving, but they'll sell those eventually once the price comes down. These 5 shows appear to be the worst selling. These figures are according to the TM maps, not counting resale tickets (because they are technically already sold).
Tulsa- 1,800 unsold, mostly rear stage uppers. Will be sold out.
St. Louis- 2800 unsold. U2 played to 19,000+ here in 2005, so they've already sold over 16,000.
LA 2- 2500 unsold. Over saturation mostly, will be sold out. (Capacity 16,700 in 2015)
Chicago 2- 3200 unsold, also oversaturation. They'll have to reduce some of those upper levels, but they'll probably fill it. (Capacity 19,000 in 2015)
San Jose 2- 4000+ unsold. It's going to be interesting to see what they do with this show. (Capacity 17,500 in 2015)
So while the picture may seem bleak, these numbers aren't entirely awful. The vast majority of arena concerts DON'T play in 360. So Coldplay "sold out" the same St. Louis arena at 13,960, even though they could've potentially fit another 5-6,000 in there. The truth is most bands cannot fill the seats behind the stage. I saw Bruce Springsteen a few years ago, and he didn't sell all the seats behind the stage, in fact the rear upper level was completely empty. Same for the Garth Brooks show I went to. Nobody seemed to care.