I am running openSUSE Leap 42.1 with latest wicked version 0.6.33 but older
versions of wicked are also affected by this (tested with 0.6.28 to 0.6.33).

On one of my machines, running "ifup" on a wireless interface resulted in:

# ifup <wireless interface>
<wireless interface>           device-not-running

Running in debug mode gave a hint it might be related to rfkill settings, but

rfkill list wifi
0: compal-wifi: Wireless LAN
        Soft blocked: no
        Hard blocked: no
2: phy0: Wireless LAN
        Soft blocked: no
        Hard blocked: no

everything is fine there.

However, there actually IS a wireless interface being blocked

# rfkill list 
0: compal-wifi: Wireless LAN
        Soft blocked: no
        Hard blocked: no
1: compal-bluetooth: Bluetooth
        Soft blocked: yes
        Hard blocked: no
2: phy0: Wireless LAN
        Soft blocked: no
        Hard blocked: no

as I actually only enable my bluetooth device when needed.

Now here is the fun part, after unblocking the bluetooth device

rfkill unblock all

rfkill list

# rfkill list 
0: compal-wifi: Wireless LAN
        Soft blocked: no
        Hard blocked: no
1: compal-bluetooth: Bluetooth
        Soft blocked: no
        Hard blocked: no
2: phy0: Wireless LAN
        Soft blocked: no
        Hard blocked: no
3: hci0: Bluetooth
        Soft blocked: no
        Hard blocked: no

running 

ifup <wireless interface>

works as expected.

Additionally, if I add a second (USB) Wireless interface and block only one of
them via rfkill, ifup will fail on both interfaces including the one not being
blocked by rfkill.

# rfkill list
0: compal-wifi: Wireless LAN
        Soft blocked: no
        Hard blocked: no
1: compal-bluetooth: Bluetooth
        Soft blocked: no
        Hard blocked: no
2: phy0: Wireless LAN
        Soft blocked: no
        Hard blocked: no
3: hci0: Bluetooth
        Soft blocked: no
        Hard blocked: no
4: phy1: Wireless LAN
        Soft blocked: no
        Hard blocked: no

-> two wireless interfaces, no let's block the first one (PCI card):

# rfkill block 2
# rfkill list 
0: compal-wifi: Wireless LAN
        Soft blocked: no
        Hard blocked: no
1: compal-bluetooth: Bluetooth
        Soft blocked: no
        Hard blocked: no
2: phy0: Wireless LAN
        Soft blocked: yes
        Hard blocked: no
3: hci0: Bluetooth
        Soft blocked: no
        Hard blocked: no
4: phy5: Wireless LAN
        Soft blocked: no
        Hard blocked: no

However, the USB dongle (name: "wlan1") should still work, it is not block.
but:

# ifup wlan1
wlan1           device-not-running

In a nutshell, wicked seems to misinterpret the rfkill state of devices.

If there is _one_ device blocked by rfkill, even if that is not a wifi
interface (i.e. bluetooth), wicked will assume _all_ wireless interfaces are
being blocked by rfkill and ifup will not work on _any_ wireless device.

A second (tiny) problem related to wicked and wireless interfaces is related to
the setting

MTU='<some value>'

in the respective ifcfg-file.

This setting is ignored only(?) on wireless interfaces, but it still works as
expected on wired interfaces.

AK