That would be true if we were still in the Silver Age. However, that is no longer the case. There are many things in comics, in Batman comics in particular, that started out as things just there for kids appeal or for shock value. Robin was included as one of those things. As time passed though, comics became more mature (barely to no kids read mainstream comics on a constant basis these days) and a lot of things were given substance. It is true that Robin started out as nothing but a gimmick pandering to kids but in today's Post-Crisis Modern world of DC Comics, Robin is a compelling character with a purpose of existing in the Batman mythos that works in the context of the narrative. Things have been that way since the early 1990's.
And also turned him into a boring and generic Gary Stu who always seems to be right and can do no wrong. He is a generic idealist cop archetype. Not that all idealist cops are automatically boring and generic with no character. There are plenty of interesting ones out there (i.e. Gordon) but Blake came off to me as the generic idealist cop that I have seen already in many many films.
Now that I think about it, even his name sounds like the name of a boring and generic Gary Stu. John Blake. Meh. Sounds like the new "John Smith". And just to clarify things in case someone reading this is misinterpreting things, I'm
not saying that his name constitutes to him coming off as boring and generic to me in any way. I'm just making a funny observation here.
I don't have a problem with characters not from the comics added in. I always liked Agent Coulson and other original characters from other comic book films. As I said, my problem with Blake is that he is boring. I consider him a vacuum because we have to spend precious screen time with a boring character like him as opposed to focusing on characters with a more interesting personality. Heck, not even that. Just characters with a personality.
And yes, the ending would have been completely different if we would have cut out Blake but that is a good thing.
It depends on what you mean by "legacy". It is true that Bruce has trained kids like Dick Grayson and Tim Drake but he did not train them with the intention that they will one day take up the Batman mantle. He trained them because they, much like Bruce at their age, sought the training required to fight crime. However, Nightwing and Red Robin do not live in Batman's shadow or are Batman's sidekicks (even though some writers often think they are). They are their own men. Bruce gave them the training and whatever they did after that point was entirely up to them. The Nightwing persona is just a fitting to Dick Grayson as the Batman persona is to Bruce Wayne. Both Batman and his "sons" have no desire for any of them to become Batman.
If you're referring to legacy being a part of the Batman mythos in the sense that Batman is a legacy character and that the mantle can be passed on, that is false. In fact, that goes against everything Batman is all about. Along with Superman, Batman is literally the
last superhero to ever be a legacy character. Batman is not a mantle that can be passed down generation to generation like the Flash and Green Lantern mantles. Batman is the byproduct of Bruce Wayne's scarred psychological mind. There is no Batman without Bruce Wayne. The whole message behind Batman is that Bruce Wayne is literally the only man to have ever achieved the impossible: He has mastered everything there is to master and has transformed himself into a demon in human form through his sorrows. That is something no one can do. It takes a ridiculous commitment to become Batman that no person can have. Not anyone can be Batman. Batman is and forever will be a part of Bruce. The thing inside him that drives Batman to do what he does and makes him literally the most motivated superhero (that is not an exaggeration) all comes from Bruce Wayne. Sure that you can have guys like Dick Grayson and Tim Drake take his place temporarily while he is missing or considered dead but no one can permanently take his place because there can be no one who can truly replace Bruce and bring the same drive to Batman that Bruce does, something that all his sidekicks know and respect. This is why I find the entire message of TDKR to be very anti-Batman. The idea that anyone can be Batman and that Batman is a legacy character whose mantle can be passed down completely flies in the face of the essence of Batman.
Out of all the stories in all the Batman mediums in the 74 years that Batman has existed for, the only time the idea of Batman being a legacy whose mantle is passed down to someone else has ever worked while still staying 100% true to everything that Batman is all about was in Batman Beyond. I tip my hat to Bruce Timm and Paul Dini for being able to pull off a concept that, by its very nature, should not have worked at all. Sadly, miracles only happen once in a lifetime. I could be wrong but I don't think I will ever see it be pulled off again, or at least not as good as they did. Ironically, what made the concept of Batman Beyond work was that they put emphasis on the fact that it
is impossible to become Batman and that only Bruce can do it. We saw how far Amanda Waller had to go and how dirty she had to get her hands in order to create a second Batman. What she did and the boundaries she crossed to do it is absolutely disgusting, and that is the beauty of it. There are many other reasons as to why it worked (such as the fact that Terry was just as mentally scarred as Bruce but for the exact opposite reasons) but that is probably the main reason. And even in the end, they still established that Batman will always be a part of Bruce Wayne in a way it isn't part of anyone else (including Terry).
I never said I disliked him. He was one of the best parts of BB IMO. What I said is that John Blake is essentially a 2.0 version of the Gordon from BB. The only difference is that he is nowhere as interesting as Gordon in BB was.