While Smallville went full DC in it's later seasons with the Green Arrow, JSA (Notably Hawkman, Dr. Fate, and Stargirl), Booster Gold, Blue Beetle, Wonder Twins, Cyborg, Impulse, Aquaman, Mera, Zatanna, Black Canary, Superboy, Supergirl, Legion of Super-Heroes (Notably Cosmic Boy, Saturn Girl, and Lightning Lad), Speedy (Mia Dearden), Rick Flag, Suicide Squad, Amanda Waller, Maxwell Lord, and even some of the Apokolips New Gods.
It felt like Arrow was more taking the Nolan approach when it started with a more realistic world and only nods to the comics like Star City with Starling City, Thea was nicknamed Speedy, even GA was just Arrow, and then Laurel being Laurel and not Dinah. I think they weren't going to do a proper Black Canary at first but once Sara became popular and Flash became a no pun intended run away hit things changed. Add to the fact Oliver just on the show was a better fit with Felicity over Laurel hey I hated what Olicity did to the show but can admit it was the better pairing. Add all that together and Laurel and the Black Canary character was also going to be a mess and its amazing they salvaged it with Sara on Legends, Earth 2 Laurel, and Dinah Drake at all.
Side note it is funny how a superhero show as grounded in reality as season one Arrow was ended with Crisis on Infinite Earths.