We got around this issue by storing the SSID + Passkeys that we want to look for in an external NAND flash. You could also store them in an unused page in the ROM of your Micro.
When you boot up, you can call wwd_wifi_scan with the SSID of interest, and then call wwd_wifi_join_specific with the information from your scan result.
We pretty much only use WWD (the lower layer to WICED) because using all of WICED was too heavy for our application. We also do not use the DCT at all.
You will have to make some sort of tool or interface so that your devices can have their new SSID configurations configured after compile time.