Meh, not good to do. But, Ras Al Ghul is not needed. How could he really tie in with Bane and Catwoman in these movies?

See I never got that whole thing about people thinking Two-Face was coming back. Not to single you out, cause LOTS of people thought that. It just didn't make sense to me. Let's break it down.

Let's say Two-Face didn't die. That means Batman and Gordon would both know he was still alive. Thus, they had to know he would've been coming back to wreak havoc since he had gone off the deep end. Thus, the whole "let's make him a martyr and Batman will be the bad guy on the run" wouldn't last long at all. Not to mention, police swarmed the place not long after. So if he wasn't dead they would've found him alive, or his body was missing. In which case it would've been a much bigger conspiracy/cover up with practically the whole police department involved in it.

Even if you can explain the absence of a body or the mass cover-up, you're still left with Two-Face showing back up not long after Batman is on the run. And obviously people are going to recognize Two-Face as being Harvey Dent. Thus, they're going to quickly realize Batman isn't the bad guy. Therefore, the entire cliffhanger of Batman being on the run from TDK is quickly lost in TDKR and is completely wasted.

It just wouldn't make sense.

True, you do make great points, just thought maybe he'd end up in Arkham, or something, but they know what they're doing, and Two-Face would probably make it overfilled with villains.

However, when do villians ever die in the comics?

In an instance that this is Nolans run, so its like his 12 part series so whatever happens happens because its his world. So in otherwords Two Face dies in his world, the next director could do whatever and start clean just like a new 12 part seres.

However you could easily bring back Two Face and erase everything. They do it in the cartoons all the time. Perhaps he finally gets a "heart" and comes back to let Batman not be the bad guy? Its all possible, not saying it will happen or has any chance, but its possible. I wouldnt be suprised to see him appear.