This has been bugging me for a while now....for military strategy buffs

1. Remember the scene where the orcs were posiitoned outside Helm's Deep? Why did Aragorn tell the archers to hold their fire? Wouldn't it make sense to let the archers fire at will as soon as they got in range? Why wait for them to get organized, come into formation, and get dangerously close?


2. Ehen the orcs managed to blow up a section of the wall, the archers were doing a good job holding them back. Why on earth did Aragorn tell them to charge the orcs? They could have held them at a distance with arrows, but instead they got their skinny asses kicked by twice-as-big orcs...

3. Why did Gandalf run off to fetch Eomyr, when he could have easily turned the tide at Helm's Deep if he just stayed put and blasted the orcs with magic? He's a white wizard di ba?

4. why was the only weak section of Helm's Deep -- the drain where the orcs placed the mines/bombs -- left unguarded? Even if the orcs didn't have any bombs, they could have rammed the fence a few times and get through(although it'd be tough squeezing orcs through that opening)

5. Why didn't Elrond send additional troops after sending the first one?