Never had a Play store issue and can't imagine what caused that. The camera was average on the Swift and I need to have a proper play with the Swift 2 Plus.
As for 5GHz Wi-Fi, or lack of, the chipset offers 802.11ac 5GHz according to the specs. Funnily enough, at the original Swift launch the Qualcomm slide said 5GHz then too. So it must be a cost saving exercise.
Many people will suffer congestion issues on 2.4, and much slower speeds (a factor if sharing a data connection over Wi-Fi or transferring data over a local network). It's not a massive problem but certainly disappointing as the cost saving must be very slight.