Is wonderwoman just never going to be finished? It's weird that one of the original DC icons is unfinished in favor of characters from TT, Young Justice, or even completely minor villain characters from the main universe being done before her.
Reee, finish wonderwoman. /end
So, this is my own speculation, but I think I've seen a few other people mention it before and I think it's got some weight to it.
There are a few popular characters that are being held out on (Ex: Wonderwoman, Starfire, Harley, etc.), because they can be used as an emergency chute of sorts. Should his Patreon ever really turn on him, and pledges start being reduced because of his delays/lack of content/bugs/etc., he can rip the chord on one of those characters and say:
"Listen guys, I'm really sorry for the lack of quality in that last update, but this next one will have [POPULAR CHARACTER THAT SHOULD HAVE BEEN COMPLETED YEARS AGO]! Aren't you excited for it! I promise this next one will be good!"
Then he'll actually get an update done on time for once, and everyone will be impressed for completing the bare minimum, before things return to the norm of month(s) long delays and obscure characters that were of low interest for most people.
I can't remember the exact timeline here, but if I remember correctly, this was roughly how Raven was finished. There was a backlash to one of his updates, his Patreon retracted instead of growing, and so he promptly put Raven into the next update which was on time, if not early, for once.
Someone may correct me if my Raven details are wrong, but I still think this is pretty on point for the last few years of his development, and why some characters have taken so long to be released.