I have my wifi sleep policy set to Never after undoing the wifi lockup fix that was put in a few builds back. And actually even though it's set to never, in the previous builds, now and again when I wake out of sleep, I notice that the wifi is turned off so whatever was killing data connections must also be killing the wifi connections. However, since I installed the 10-20 build, I have not seen my wifi dead coming out of sleep yet so maybe the data connection fixes that TG and Isaac implemented fixed the wifi getting killed also.
So, if you're adventurous, you can try disabling the wifi lockup fix and then setting your wifi sleep policy to Never. Of course, ymmv and you may get lockups but my phone never really got lockups with the wifi on while sleeping--guess I must be one of the lucky ones.
To disable the wifi lockup fix:
open /system/etc/firmware/wlan/qcom_cfg.ini in the text editor
change gEnableSuspend=2 to gEnableSuspend=3
I do this directly on the phone using ES File Explorer (free on market) with the Root Explorer option enabled and the Mount File System option enabled in the Settings so that I can save my changes back to the phone.
And I suppose, if you wanted, you could change the file in the Zip file first before flashing the update.