Reason number 1,
Plot holes bigger then the halo rings.
A long time ago the forerunners were the wise and just guardians of the galaxy. Suddenly ancient humans came out of nowhere because they were running away from the flood. The humans destroyed a few forerunner planets in an effort to stop the flood from spreading, which resulted in a long and bloody conflict between the two races. PAUSE
Why didn't the humans try to warn the forerunners about the flood? Why did the forerunners react with violence instead of trying to find out why the humans were attacking them? I mean aren't they supposed to be these benevolent safe guarders of life? Neither the humans nor the forerunners tried to find a diplomatic solution?
PLAY The humans lost the war, and the didact reset their DNA so they became cavemen again and put them on Earth PAUSE
Martian man hunter rip off.
PLAY Eventually the forerunner realized that the humans were only attacking them because they were trying to stop the flood from spreading. It was too late however, and the flood starting kicking the forerunners' asses. In a failed attempt to gain immortality and transcendence, they found a means of making organic beings into inorganic lifeless scary bug robots that were the ultimate weapons against the flood. They began turning themselves into the "Promethean knights" to combat the parasite. PAUSE
I fail to see the point of turning forerunners into promethean knights. Why not just make tons flood killing robots? I mean seriously. "Hey, so in order to prevent you from becoming flood, we think it's a good idea for you to become a promethean knight." That's like saying, "Poor gasoline on yourself and light yourself on fire so you don't freeze to death."
PLAY To get more Promethean knights, the Didact, who went a little psycho in his hatred of humans, started turning humans into Promethean knights because he needed more. The librarian, thinking that the forerunners had failed as guardians of the galaxy, decided it would be better to set off the halo rings and kill everyone in order to rob the flood of their food source. Some sentient life would be kept on the halo rings in order to be spared, and then would be re released on their home planets. The Librarian also messed with the human DNA so that they eventually become the gaurdians of the galaxy. She shot her husband, the Didact, and put him in a little ball inside an artificial planet and sent him outside the galaxy so that he could one day be awakened.
Well apparently she had a pretty bad plan because nothing in it worked at all. The covenant races advanced faster then the humans, the flood that they kept in tubes for some stupid reason got released, and the didact got released too early.
I'd say halo, halo 2, halo 3, and halo Reach have great storylines. It's halo 4 that screwed it all up.
Reason number 2
The didact is a very stereotypical villain.
A friend of mine called him, "Darth Sideos in Lord Saurons armor." His lines are cool, his voice is cool, but come on. Did we really need a halo villain that could use the force? The point of the forerunners was that they were mysterious. We all knew them as these people who terraformed planets for the lulz, and we all wondered what they were capable of. It was better that way. Now they are just like any other highly advanced ancient alien nemesis. The didact can read minds and pick things up with his mind. Next thing you know he's going to say, "Take me to your leader." And come on dude. THe outfit. You know how I knew he was going to the bad guy as soon as I saw him? It wasn't because I understood the plot of the game, it was because he was dressed in black armor with horns and gave off an orange/red aura.
Reason number 3
"If it aint broke, don't fix it." As they say. The Elites looked cool in the other games. Why did they have to change them? I thought I was watching the land before time for a second when I first played halo 4.
Reason number 4
I shouldn't have to youtube all the terminal videos and read a plot summary on halo wiki to understand the story of the the game, and that's what I had to do. The story was not developed at all. They tried to explain too much in too little time. Did anybody catch what the librarian was talking about?
Reason number 5
Cortana's death was unnecessary. She's a sassy AI that Master Chief is really attached to because he has no friends. We all liked her because she provides comedic relief. It was a little distressing to think that she might die in halo 2 or halo 3, and when she lived we were a happy. Now when we are trying to play the game and we have to listen to her "Go rampant" the entire time. It wasn't sad when she died, it was more of a "What did I just watch?" sort of feeling. Why kill off Master Chiefs AI side kick in such a dramatic creepy human-hologram robot kind of love intrest fashion?
In light of this, me and my friends have proposed an ending that will forever be canon to us.
Master Chief is never seen again, although some slipspace anomalies near Reach were detected a few weeks after the ark was destroyed. Investigations found nothing. Legend has it that the aging spartan, with the help of his trusty AI companion found their way to Reach, where he currently resides by the graves of his fellow Spartans. All across the galaxy people sing of the soldier who saved humanity, and they say "the Master Chief" remains ready to save humanity should it fall into peril once again.