I think you're right. They've talked about how they want the names to make it clear enough for new players not to accidentally buy the wrong stuff, so this will probably have to indicate that it is some sort of advanced rules of the game you should not be buying if you don't unless you already have experience with the game. Maybe "Advanced Dungeons & Dragons Players Handbook".
In seriousness, I wouldn't be surprised if they put "Advanced" in the title, since people who know/remember the history would already know this book is something different, coming out in the 21st century as it is, while those new to the game probably have never heard of the old terminology and would take the term at face value. "Players Handbook" wouldn't be in the title though, as it would be misleading.