Yes, but TDK drove that idea even further, and showed us that Bruce didn't want any masked Batmen running around trying to be the hero. That was shown to us explicitly in TDK, and the main theme of the movie was to give the people of Gotham a hero with a real face --the true hero of Gotham. Yes, Bruce thought of his endeavor as being finite, and yes, he wanted to shake the people out of apathy, but at the same time, he didn't want people running around as superheros, as he didn't want to create more escalation. He wanted the people of Gotham to stand up against the crimes themselves...real people, actual citizens, not masked vigilantes. The "symbol" he was talking about wasn't an actual Batsymbol(as he never even created it yet), or a vigilante symbol, it was a symbol of truth, hope and justice. Something that was lost on the city at the time. And you know who also represented that symbol before Blake? Gordon, Rachel, Harvey, police officers etc. Why was Blake needed again? Oh, so Batman could retire with a twist ending, and then contradict a main theme in both BB and TDK?
Now cut to TDKR, and we have a contradiction of the main themes represented with the other movies. Bruce never even wanted other masked vigilantes taking over, which was spelled out very clearly in TDK when Alfred mentioned more Batmen sightings, and then Bruce says, "that's not what I had in mind when I said I wanted to inspire". Bruce wanted the system to work properly(and normally), which is why he appointed Harvey to be the new face of Gotham, because he was the hero he could never be. Why all the sudden is he now instructing Blake to wear masks when he goes out to fight? At first Bruce didn't want Batmen running around Gotham, he wanted a hero with a face like an ordinary citizen, but now he wants a "hot head" running around with a mask on, who is apposed to working within the system itself? I mean, which movie got it wrong: TDK or TDKR? Why is Blake's character needed again, when not only were we shown other characters just like him in this series, but his character contradicts everything that was setup before it? It's like the Nolans remembered to implement the mentioning of Harvey and Rachel in TDKR, but forgot what the characters actually represented, and then added Blake into the equation, which contradicts so many things before it.
I mean, seriously, if Batman was just going to retire and give over his cape to someone else, what was the entire point of covering up Harvey's crimes? What was the point of the entire movie of TDK? Because if all he wanted was to have a Batman or a masked vigilante running around the streets cleaning up crimes, why didn't he just do it himself, instead of giving so much emphasis over to Havery while taking the blame and having to retire right afterwords? Did John Blake's character work in TDKR? Ummm, if you forget about the other two movies, then sure, his character makes "perfect sense".