It's Shakespearian irony. Bane was specifically emphasized to deal out death in a nonchalant unapologetic manner, discarded with ease and instantly forgotten. It's not about what you want, it's about what carries the most weight. Bane was defeated in the same manner in which he dealt defeat to those around him. It's fitting.
Again, we know he has the means to get back into the city, as established in great detail above. While you can wish you saw it, ultimately, it wouldn't have had a real place in the film. Bruce showing seemingly out of nowhere is necessary for the final 45 minutes to function dramatically. He's back, he has newfound purpose, clarity, and insight into himself, the people around him, and how to save his beloved city. A 'break into Gotham' sequence, or almost any mention of how that happened, would've detracted from the purity of establishing those qualities around Bruce's return to the city. No matter how effective it was executed into the film, it would've lessened the potency and focus on those completely key concepts going into the final stretch of the film.
Additionally, the public surely envisions Batman returned once and either was defeated by Bane in the takeover, or, gave up. A powerful symbol across the city ignited on a key landmark the whole city can see communicates not only his return in as wide and powerful a way, but it does this with the chief iconography of the character, dramatically beginning his 'rise' in Gotham in a symbolic way.
-Vader
Again, we know he has the means to get back into the city, as established in great detail above. While you can wish you saw it, ultimately, it wouldn't have had a real place in the film. Bruce showing seemingly out of nowhere is necessary for the final 45 minutes to function dramatically. He's back, he has newfound purpose, clarity, and insight into himself, the people around him, and how to save his beloved city. A 'break into Gotham' sequence, or almost any mention of how that happened, would've detracted from the purity of establishing those qualities around Bruce's return to the city. No matter how effective it was executed into the film, it would've lessened the potency and focus on those completely key concepts going into the final stretch of the film.
Additionally, the public surely envisions Batman returned once and either was defeated by Bane in the takeover, or, gave up. A powerful symbol across the city ignited on a key landmark the whole city can see communicates not only his return in as wide and powerful a way, but it does this with the chief iconography of the character, dramatically beginning his 'rise' in Gotham in a symbolic way.
-Vader