>>317773
A lot of Arrow is ripped off/adapted from the Batman mythos, Green Arrow on his own just doesn't have that much lore to use. Plus Arrow first came out in 2012, right after Dark Knight Rises, and they made it very clear they were after the Nolan audience. Season 1 is pretty much Batman Begins starring edgy Robin Hood. Then there's the whole "Ra's Al Ghul wants Oliver to be his heir" thing in season 3.
They sometimes have fun with it though. Like >>317782 said, when Oliver starts calling her Overwatch he admits he wanted Oracle first, but the name was already taken.