Banter: My main complaint with The Dark Knight Rises

Okay, so this post is designed purely for those who have seen The Dark Knight Rises, and it will contain heavy spoilers involving the plot, character developments and overall narrative structure. So much so that I will blank out the majority of it to prevent people from accidentally reading it.

Why? Because from all the reviews I have read, watched and heard, I have yet to hear this as an issue, and to me it is a huge mistake with big bells hanging off it.


So, for those of you who have watched the film, highlight the text below to read on, but for everyone else, this post does not exist!


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So, the villains of The Dark Knight Rises are specifically Bane and Miranda, Miranda is revealed at the end as Ra's Al Ghul's daughter and ultimately the one in charge. Bane is only the muscle leading the attack on Gotham, destroying Batman, disabling the Police force and stealing the Fusion Core from Wayne Enterprises and holding the city hostage... Miranda does next to nothing.


Oh, except taking full control of Wayne Enterprises from Bruce...


Hang on...


The Fusion Core is the endgame for their plan to destroy Gotham; get the Core and they can hold Gotham hostage, and the Core is owned by Wayne Enterprises...


So, why didn't Miranda seduce Bruce Wayne and take the company (as she did) and just... take the Core? Easy. She could do anything as the head of WE, bring in some new "security staff", totally override the company's infrastructure and while Bane was out terrorising the people, she could say, for example:
"Hey Bruce, they might be after the Fusion Core, we should defend and/or move it."
Only to take control of it there and then. Or even more insidious, just not have the Occupy-Gotham plan, just infest WE with League of Shadows operatives over several years, set off the Fusion Core, kill Lucious Fox (that would be heart breaking...) and sit back and relax.
(and they obviously knew everything about Wayne Enterprises, they knew about the hidden "Advanced Sciences" wing and built Bane's "home" underneath it!)


I do not understand why she waited so long before revealing herself, or have such an elaborate brute-force attack to get the Core when she was already in control of Wayne Enterprises. One of the - if not the - most influential companies in Gotham!


To be honest, I thought Bruce was a dimwit for giving her control of the company from the moment it was suggested...
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So, I can say to those people not reading this post that you shouldn't read the comments to it either! If there are any comments, but I am curious what people think. 
I need to watch the film again... but this one factor really, really bothers me and was too long winded to put in the review.
...
It is still a good film though!