It won't fix the world, but it's not an insignificant issue. Bin Laden WAS an inspirational leader to many anti-Western folks and insurgents and terrorist groups. He was a unifier, a symbol and he could persuade people to get along with each other. Believe it or not, Terrorists feel emotions too - they get angry, impassioned, hopeful and all that sort of stuff. Symbols matter to them just as much as they do to us. Killing Bin Laden will make them angry.
Now, we actually WANT them to be angry. Angry people make mistakes. Angry people are hasty. Angry people rush ahead and do foolish things. Killing Bin Laden might make some terrorists so eager for revenge, that they trip up, making an unmasked phone call, meet with someone too soon or travel openly.
This also disrupts the networks. Bin Laden was HEAVILY protected and guarded. Only his most absolutely trusted bodyguards were let anywhere near him. NOTHING electronic of ANY SORT was allowed near him - not even one phone line. He communicated entirely by spoken word to couriers and messengers, who travelled on foot. It took years and years and years to track him down, precisely because he was purposefully using extremely primitive communication techniques to ensure that the US could never get a bead on his location.
And despite AAAAALLLLL that, he's dead. Despite the enormous protection and deception surrounding his location, he was still caught. This will give the terrorists pause - they know that the US couldn't have traced a phone call - they weren't using phones. They know the US couldn't have used satellites to find him - he travelled in disguise on donkey and horseback. The only way the US could have found him was by human intelligence sources. Someone betrayed him. Who was it? How many others have betrayed Bin Laden? Who can they trust? Their entire circle of trust is smashed and broken - they have no idea who to trust, who might be a spy working for the West. They're going to go absolutely paranoid over this, and paranoid people can't work effectively. When you have to change location every week for fear of being caught, it hampers your ability to plan. When EVERY message HAS to be delivered on foot, it hampers your ability to organize an attack.
The death of Bin Laden does NOT spell the end of terrorism and anti-Western insurgents. But it DOES disrupt their plans, it introduces a healthy dose of fear and paranoia and recrimination and many terrorist groups, having lost their uniting leader, will split, will challenge each other for authority, and will become paranoid about being caught. This one move will have disrupted terrorist activity for years, as now pretty much every leader is absolutely petrified of being caught - if they got to Bin Laden, who ELSE can they get to!? You don't think they don't feel fear? Why is it that they always send some poor shmuck to blow himself up, but the leaders never do? If they really weren't afraid of being killed, why the elaborate, paranoid preparation and hiding? These terrorist leaders are just as afraid of death as anyone else. They aren't stupid and gullible like your average suicide bomber (who tend to be directionless angry teens guilt-pressured into it), they are smart and conniving and use other people to die in their place. Because Bin Laden's dead, every big-wig terrorist or insurgent leader is worried that they will be next and they'll spend the next 2 years just trying to re-cultivate a sense of security and trust.
Not only that - Bin Laden's compound must have had some seriously valuable information. It did go up in flames, but no doubt some papers and files were taken by US forces.
This will hurt the terrorist groups. It will not spell the end of them - oh no, they're not going anywhere for a good while yet - but it disrupts their activities, it forces them to play defence for a while and that's good. Maybe, hopefully, some of them will be so enraged by the death of Bin Laden, that they'll do something stupid like make a direct call on his cellphone to a cell leader, who can then be promptly killed by a predator drone.