Well then it can't be the worst... Hmm we will have to do some digging for worst Batman movie but let's start by accepting bat nipples and giant bombs that say "boom!" on them automatically elevate the movies.
Batman & Robin, though terrible, at least looked nice. Good colour palette and cinematography. Good set design and special effects. Decent acting all round. It's clearly harking back to technicolour Batman. It was schlock but that was clear from the outset. There was no hope of it ever being anything but a movie to kill an hour and a half. I'd watch it with my 8 year old gladly.
This travesty was made by one of the (supposed) best directors of his age (not evidenced by his largely awful movies, which are pompous style over substance) but it was a mess from start to finish. Poor casting, poor dialogue apparently written by a 12 year old, numerous ridiculous plot points. Batman was barely in the movie, apart from the lengthy and ridiculous broken back scenes. It was basically a movie about Joseph Gordon Levitt's character.
It was the stark opposite of the classic that preceded it.
For me, the worst is either Batman and Robin, or the first 30 minutes of The Killing Joke where Batman fucked Batgirl (say what you will about their relationship, it is just plain weird of them to become romantically involved).
As for the Dark Knight Rises, I see where you're coming from. I think Nolan directed the last movie in such a way so that people would not crave for another sequel. It's not bad, but it is not titilating. A lot of directors "underperform" on their works so that the audience would not demand for another. Some movies just doesn't deserve more sequels than needed.