A lot of the markets visited on the 2009 Euro tour might have recharged their demand after 2 years. If U2 had a hit album/single during ticket sales, thing would be even better. They could probably do a decent sized leg, really.
Dublin- 2, maybe 3?
Belfast- 1
Edinburgh- 1
London- 2? If the album is a hit, then maybe.
Another show in England, somewhere.
Amsterdam-2
Rumored Bucharest show.
1 show in Eastern Europe- Split? Belgrade? Sofia?
Stockholm- 1
France-1 (Lyon, perhaps? Or Paris again, why not? Sold out everytime so far.)
Italy- 1. Florence?
Madrid?
Norway- I know there's not a sufficient stadium, so they say, but if they want the $ bad enough, they'll make it happen. Look at the venue in Horsens, for example. If they're playing places like that, they might as well play the grandstand at my local county fair!
Prague? The only stadium big enough is the 200,000 Strohav Stadium, so maybe not.
One could say demand has been met for places like Sweden, France, Spain and Italy based on the # of shows, and normally that'd be right. However, this is spread out over 3 summers. I think in each other these countries they could do one show based on the fact that it's been an entire year or more since they toured there. Combine that with the fact that the new album might restart and reboot demand for U2, and you could be looking at more shows.
One thing is for sure... demand has probably been met and exceeded in Germany.