For me it will be definately:
Rotterdam, Antwerp and Oberhausen.
Also thinking about Bournemouth and Glasgow.
I hope we will have the opportunity to buy pre-sale tickets
If you need a hotel it's nicer to stay at the Tryp in my opinion. There are some nice bars and restaurants and the next day you can take the train/tram back to the Central Station. Oberhausen itself is ugly, so the hotel near the CentrO is nicer to stay and enjoy a drink with other fans