Its not just that, but every once and a while one of the magazines comes out with a list of how much actors on tv shows get paid per episode. It can be anywhere from $50,000 per episode to almost $500,000. Multiply that by say thirteen episodes, which makes that $650,000 for at least one of the main cast. So, there goes pretty much a major chunk of a shows budget. Which is why most shows have been held up during contract negotiations with various actors.
But, what has me scratching my head is these articles coming out. They are getting fans all excited about the show, and this news could make fans run for the hills worried that the first season isn't going to be good, so why bother? Then ratings will tank, show will be pulled and certain shows with the same basic story elements will take the time slot. I agree, they can structure a show to which character with powers can appear, when powers can be used and how much. The Flash has been pretty good about that. Like the shapeshifter episode in season one. A few shifting effects spread out, but largely using the same actors. You'd think they'd be behind the show because they have found hits with the Flash, and Arrow dominating their time slots. Supergirl is an effects heavy show as they are bringing more superpowered characters there. But, I also agree if they skip most of the filler stuff, keep the romance to a minimum and focus on the key story elements the show might have a chance.
Though perhaps another reason for this "worry" is that another article came out saying that The Vampire Diaries and the Originals is sinking in ratings, and being moved to Friday to make way for Legends of Tomorrow is basically one last stop before being cancelled. The CW probably worried about losing another major audience, so, their weighing their options: Keep The Originals and The Vampire Diaries who have an established fanbase, or risk a roll of the dice that Legends of Tomorrow will be a hit.
On another note: There is a rumor circulating about a Green Lantern movie reboot, though it is going to be more like Lethal Weapon in space. What?!