I just ran through three seasons of Arrow and one of The Flash in about six weeks, and I think Arrow’s Weird Level rose too quickly in two and a half years, partially to match The Flash. Which considering the newer show quickly develops into a world with super-speed, weather control and time travel in the first episode, with a tease of a giant telepathic gorilla as well, may not have helped the “no-nonsense” street-level vigilante show all that much.
A superhero universe can quickly develop a really high Weird Level, but one that starts with a skilled normal fighting gangsters and goes no weirder than that for a year might not be the best fit. Maybe it should have brought in a couple of weirder villains earlier if expanding to something like The Flash was the plan.
Stephen Amell has mentioned going more grounded in future now there are multiple shows with different tones... while discussing the possibility of a crossover and/or musical. It may be too late...
Also, lots of support teams on earbuds. Pretty common in modern action shows, the Intercom Girlfriend from video games and the like. In games it lets a non-combat PC contribute to fights, and lets everybody talk IC even though their characters aren’t there. (See the third of Five Things Roleplayers Can Learn From Leverage by Steve D.) And private prisons, which get around various practical issues but don’t get questioned very often. And not telling the female romantic lead while spilling to just about everyone else. Which is... odd.
(I was also perplexed that R’as al Ghul was a scruffy Australian and Captain Boomerang was neither of those things, but never mind.)
Anyway, how do you set up a reliable Weird Level? Track it up a bit slower, I think. Introduce some more Weird in that first year - a good call for a superhero-based show anyway, in case you have any plans for weirder stuff later on. A ghost here, a vampire there. And bring in the crazy assassins a bit earlier in particular if they’re going to be that big a deal.