Great ideas that fall flat

I've really gotten into graphic novels this year. I'm now a fan of Saga, Fables, the Walking Dead and Y the Last Man. I've almost finished Y the Last Man and I've both enjoyed it and at the same time thought it was a bit meh. Y has a great start: a plague wipes out every man, boy, male fetus and male animal on the planet leaving women to inherit the world and one man - Yorick - and his pet male monkey alive. I loved this series at first. The premise was utterly fascinating. Can you imagine a world without men? There would be some countries in the world that would fall apart because women are restricted from doing so many things. But other countries would probably be able to pick themselves up relatively quick and get back on with things. Y makes you think about how we treat women and makes you ask the question why do we restrict women from doing so many jobs? Why do we let gender stereotypes restrict what both men and women can do for a living? Men should be able to work with children and women should be able to be CEO's and brickies and tradies and truck drivers in larger numbers. I think gender stereotypes are so deeply ingrained in us as a society that we don't even realize that we are passing them on. Some of these stereotypes I'm all right with. I think women should have equal rights but like HELL I am going to squish a mouse. Nope. That's what men are for. Men with their giant feet. The problem with stories like Y the Last Man is that they have these great ideas that that...fall flat. Y has a great opening, and then nothing much happens for a while. The plot kind of fizzles out. And I've noticed this is a trend. A lot of stories have an explosive beginning and then the middle is flat and boring. Like in Lord of the Rings. I tried to read those books. I got to about the end of the second before I put them down. I hate how so much of those books is devoted to the characters just walking places. I feel like a lot of these type of stories need a really good edit. I just put down Petals in the Wind after getting 200 pages into the 500 page book. I loved the first book Flowers in the Attic but the second was like a steak with a lot of fat on it. The middle of the book is completely pointless and boring. It could've been cut back a lot. I think that book would've been better if it was about 150 pages or so less and more of the plot focused on Cathy planning and executing her revenge on her mother and grandmother. A great opening (or hook) is extremely important in fiction. But do not neglect the middle of your story. You have to have a plot that has a beginning, a middle and an end. All of the exciting stuff cannot just happen at the beginning. And you can't expect the reader to read through 300 pages of nothing to get to the good stuff at the end. Edit, edit, edit.