Long thought out post warning!
I'm not too worried about it beating Avengers when it comes to the box office. It's not in 3D, it's a longer movie(less showings in a day), it's for a more mature audience(Avengers appeals to everyone, whereas Nolan's Batman has been darker and not so kid friendly), and finally it's opening up to more competition. That's all working against it, they aren't excuses to make up for a poor box office performance, as I am sure it will still do great just as TDK did, but to expect it to beat Avengers...it's not as important given all the factors at hand.
It's about quality.
I just hope the reviews are positive, and the movie can stand up against Batman Begins and The Dark Knight in terms of quality, and an argument can be made on which is better. Some people like Begins more than Dark Knight, and all I hope is that this movie can be on par with the other two highly praised films. It doesn't have to be better than either, it just has to be on par. That's it. I hope fans don't let their hype and expectations make or break the movie, and treat it with the black and white approach. It doesn't have to be amazing or crap. It can be great, but not be better than Dark Knight.
With that said, I hope and believe, that this movie will be the exception to the curse. I believe it will be on par with the other two and this series will be great from start to end. Be it not as good as the other two, better, or equal to, it'll be good enough to be on par.
As stated before, Nolan only made The Dark Knight because he felt it was a great story that was worth telling. Same goes for Rises. I remember when the word was that there would be no 3rd. However, after his vacation and giving it some thought with his brother who he writes with, he thought of another great story that caps the franchise well. Heck, he even said in an interview that one of the reasons he was hesitant to do a follow up the Dark Knight, was because he knows how often trilogies dip in quality, especially with the 3rd. It takes a lot of effort and a tremendous story, to wow an audience effectively catching lightning in a bottle 3 times in a row. It was never a for sure thing. He isn't in it for the money grab or easy check, as proven with the fact that he is calling it quits after Rises. If he just wanted money and didn't care to give a great story, i'm sure WB would be dying to keep him and have probably offered him the moon to get him to stay.
Point being, if he didn't think he could top what he has already done, or at the very least make a movie that's on par with the previous two, he had no reason to ultimately do it. He could have left it at the two and leave on a high note. He's confident, and we have no reason to doubt his ability to make it happen. He's had around 10 movies so far, all of them have been good-amazing in most people's eyes.
Beyond the points in his favor already made, it's also worth noting as discussed earlier in the thread, he's a rare case. He has directed the past 2 movies. The cast has been the same(Rachel being the exception, but not a big difference), and they all seem to have chemistry and get along, and Nolan sees something in people that bring to the table what he's looking for. The writing team has been the same. He and his brother work on the writing, so obviously the process is very cooperative and streamlined, with little kinks or internal issues. Finally, he seems to be given full freedom, no meddling or interferance from WB, as proven with him choosing the villains he wants, and him walking away when he wants etc. They know he knows what he's doing, and they let him do his thing. No forced villains or themes to sell toys etc. No re-writes making things more kid friendly or taking out key plot points etc.
Lastly, I will point out 1 last factor in Nolan's favor. The Dark Knight Rises looks to have a different feel than Batman Begins and The Dark Knight. At first it threw me off guard and I didn't know what to think, but after watching the 1st trailer a few times I was excited for a different feel. If it follows the same steps as Dark Knight, it's gonna get panned. It needs to play the same melody, but hitting different notes. The Dark Knight had a different feel than Begins and it worked. Far too many sequels of successful movies, especially the 3rd, try and be too different to the point it loses what made the 1st and/or 2nd good, or they play it safe and make it just more of the same and offer little to nothing new, leaving the audience wondering what the point was. Examples of each being Spider-man 3 being too different(cramming way too much in, and everything feeling underdeveloped and rushed), and Iron Man 2 not being different enough(imo it felt like just more of the same).
So there's really no reason for this to fail. If it does it's all on him, the actors, and the writing. With everything on his side for why it will succeed, I fully believe we will get an on par film if not better than the previous two.