Why did Master Chief forget how to hold two needlers at once?
I don't recall an instance like this. Where did you hear about him "forgetting"?
He could hold two at once in Halo 2, and he couldn't in Halo 3. I assumed he forgot how.
When did 343 Guilty Spark get that laser ability, or why didn't he use it sooner?
Using the laser consumes his processing power which he needs to think clearly.
I'll give you that he was a bit crazy in the final battle, but he clearly used it on a combat form at the end of the level Floodgate (I think), apparently because of an emergency. Why didn't he use it when the ring from Halo: CE was at risk of being blown up?
Why didn't Johnson just get on that loving pelican when Miranda told him to? It would have saved everyone a lot of trouble.
The Brutes/Flood would've taken it down. And she wanted to go down fighting like her father.
They would have had a much better chance then they had on foot.
Why doesn't the Gravemind simply kill people with those giant tentacles he used to attack the pelican?
He may have consumed worlds, but his tentacles can only go so far.
I'm mostly referring to the scene where the Chief and Arbiter were knocked off the pelican. It looked like he could have knocked them clean off that platform, but then he just left the scene and sent the army that has failed to stop them so many times before to do the job.
If energy swords can be held with one hand, why can't people hold two? The Arbiter in Halo Wars had the right idea.
Duel-wielding in most games trades accuracy for power. Apparantly, Ripa Moramee (Halo Wars Arbiter) wanted power vs. performance.
I want power more than performance, too. Why can't I pick up another sword?
Why did the UNSC get rid of all their good pistols?
They didn't. The pistols you get depend on what was being mass-produced at the time.
Why did they stop producing the good ones? Don't say price; they can give specific people specialized weapons, as is the case with the Spartan Laser.