we did find out who alexander was?
the problem with this movie was that is focused too much on who alexander was. the movie did it so much and so well to the point were we no longer cared for alexander cus he wasnt so mysterious, and cool. and so the movie lost our interest and thus all of the reports that it was horrible.
how did he conquer all the world. he did this with his mind. alexander was able to take over the world one because he was smart in battle, we saw this in the first battle. we also saw it in the second battle where he used his mens love for him to give them spirit. the other method that he used which is critical was how he incoperated the conquered lands into his world, he made them feel important. if you look at history every large empire used this method inorder to grow. and once they stopped using it they fell. alexanders empire feel because he died and his genrals didnt feel the same way about the lands as he did. rome fell when they stop respecting there ppl and the ppl outside of there empire. the only historical expection of this was the colonial empires. however this was becausea a small army could kill a big army if it was better equiped. and so rebellions could be quelled quickly and efficiently. in the end it did matter thou because the colonies still got there independance.
so in a way if you look closely at it both of your questions were answered.