In short, yes.
In the beginning God created Man to live in relationship with him. Sin has ruined this relationship and created a barrier between us and God. Throughout history man has sought to bridge this gap through his own efforts, by being 'good' or by abstaining from things in order to please God. This is religion. Most Christians would not class Christianity as a religion for the reason that there are no strict rules we have to follow, Jesus has done everything that is necessary.
Without sin, there would be no need for 'religion' at all. No one would be seeking to find God, as there would be no separation from Him to start with. In this sense, yes, the world would be better without religion.
If we accept the fact that as long as there is sin, there will be religion because of our inbuilt longing for God, we must then look at the second part of the question, regarding war.
We must avoid the mistake of blaming someone for things done in their name.
For example, if you told me that you wanted your favourite sports team to win the league that year, and I then went off and killed all the players in the opposing teams, claiming that it would guarantee your team winning, and so it was what you wanted, would it be fair for me to attribute my behaviour to you, or to generalise that behaviour to all the supporters of your team? I hope that you agree that it would not.
This is similar to religious wars.
There are countless wars that have been fought in the name of religion. Christianity cannot distance itself from this, the Crusades are a prime example of atrocities performed in the name of Christ.
However, these things are the complete opposite of the teachings of Christ himself. There are many people who would call themselves Christians, but do not necessarily reflect Christ, but, instead have their own agenda. This is not new and Christ even spoke of these people:
"Not everyone who says to me, 'Lord, Lord,' will enter the kingdom of heaven, but only he who does the will of my Father who is in heaven. Many will say to me on that day, 'Lord, Lord, did we not prophesy in your name, and in your name drive out demons and perform many miracles?' Then I will tell them plainly, 'I never knew you. Away from me, you evildoers!' (Matthew 7:21-23)
Although Christians are to be imitators of Christ, this is not something that anyone can perfectly achieve. Please do not have your view of Christ tainted by those who follow Him.
For more on this subject:
http://reason.cck.org.uk/werent-people-from-around-300-1800-ad-under-a-g...
