[tuomosipola]

1) The green ones are the Greeks, yellow ones are the Trojans. I think there should be a legend for this.

2) Needs legend. Actually, the cross might typographically be the dagger character, which usually looks like a cross. But in this case it looks a lot like a cross. I think it is used quite universally as the sign of death in books about history, and I haven't seen any other sign used instead.

I completely agree that many Wikipedia maps and graphs have this problem. The symbols and colors are not explained in the figure itself. I guess it's because they want to be able to translate them easily.