Let me put it this way: Gotham takes place before Batman is even "a thing." DC Comics told the writers "this show can take place in any time period you want, we're giving you the freedom to create an alternative storyline." And so, they wrote it. Filmed it. And it worked well because THE TEAM UNDERSTANDS the source material, because Gotham seems to click into the final product already in the market. Arrow sounds like they were given freedom, but injects their own ideologies. Like the crossover with supegirl, if I recall. Or catwoman. That SJW bullcrap.