Speaking as one of Donna's loyal fanbase, I absolutely think the character can and should be saved. There is an opportunity to showcase a powerful, established female hero/warrior related to Greek mythology with deep ties to the DC universe that already has a fanbase. I feel like it's a no-brainer. Look at the success of the Wonder Woman movie and the huge popularity the character is now enjoying with a new generation. Fans are interested in these types of stories and characters. Donna should be tossed because of her mishandled origins? Worst things have happened to characters. Hydra-Cap for instance. There's a reason this character has survived over 50 years of publication history even though her initial creation as a separate Teen Titans character was an writers mistake. It turned out to be a good mistake because Teen Titans have enjoyed immense popularity over the years. Donna suffers the same issues as the rest of Wonder Woman's supporting cast, unfortunately.
I've sounded off about this several times that WW related-characters don't get the same treatment as her contemporaries Superman and Batman. In general, I feel like DC has historically mishandled their strong, female characters. In my opinion there's no reason why Donna can't be the Nightwing to Wonder Woman. Well, minus the recent events, of course...