I expect the ratings to drop some, since that's normal for a second episode. It's not out of the question that they might rise if word of mouth spreads that it's a great guilty-pleasure show.
But I wouldn't wait for the show to stop being an ungodly mess. Either the ratings will keep it going, which will send the message to the showrunners that what they're doing is working, or the ratings will fall and it will be cancelled.
My experience is that series premieres are usually a good indication of what the show is going to like for its lifetime. They might improve some, but they don't radically change character (The Vampire Diaries
for example - the writing improved but if you weren't into the teen angst thing at the start, you still won't be into it in S3).