Then, which religions are the ones to unite the world?Yes. I believe that in their original form that most religions had the potentiality to become universal and unite the world.
How do you know if your faith is competent?In the Bayán the Báb says that every religion of the past was fit to become universal. The only reason why they failed to attain that mark was the incompetence of their followers. (Shoghi Effendi)
Here, you seem to be saying that Sharia law is not useful, because it derived from a warring age. Hence, if this is the case, you have shown that the wrong interpretation of the Quran/Hafiths, which happens in many Islamic sates, is dangerous. Therefore, Islam is dangerous. You have proven the Op's point, unless you want to refute this?Not all the laws came from the Quran but were devised for the needs of that time and may not be all suitable for this age. But in its time it united the warring tribes into one nation so it took humanity into the nation building era and many of its ideas were spread to Europe through Spain.
One thing I need to ask: you seem to think, in the Quran, Hell is state of misery. Does that mean if someone has no religion and is good then they're in heaven?
Therefore, Heaven and Hell, for you, are states of being in the world. Why would we need religion if we can achieve this without religion?