8) Blue Beetle
If everything had gone to plan, we would have seen a lot of classic hero Blue Beetle in the Arrowverse by now. However, due to the ruling of DC’s movie division, the character has been reduced to a bunch of easter eggs.
Throughout the first two seasons of Arrow, Kord Industries was frequently mentioned. Likewise, its CEO Ted Kord was even said to have invited Oliver Queen to a fundraiser at one point. This was intended to set up the character’s arrival as Blue Beetle in season three, where he would have been played by Brandon Routh.
Late in the day, however, the order came from high-up that the character was off the cards due to a planned Booster Gold and Blue Beetle movie. So, plans were changed and Routh ended up playing Ray Palmer AKA The Atom instead.