For a show that has been denied to tie into Batman vs. Superman, or any forthcoming DC movie plans, it is using a lot of Batman/Justice League stuff. I know its a comic book show, but they pour it on pretty blatantly. I never watched Smallvile, but did they pull the same thing? I understand having to dip into the well and use cross over villians because Green Arrow's Rogue Gallery isnt like Batman's, but you might as well start making DC shows and have crossover episodes so that its not Arrow: Justice League Edition
(I am not a comic nerd like some, but I know enough to make connections. I can be mistaken)
Smallville showed a lot of the justice league and others, martian manhunter, aquaman, mera, impulse, green arrow, cyborg, hawkman, dr fate, stargirl, zatanna, black canary, speedy, cosmic boy, lightning lad, saturn girl, wildcat, sandman, green lantern, atom, flash, red tornado, star spangled kid, the wonder twins, booster gold, blue beetle, superboy, supergirl.
Villians that showed up, lex, roulette, metallo, brainiac, zod, faora, toyman, maxima, plastique, icicle, doomsday, bizarro, isis, deathstroke, granny goodness, dark archer, captain cold, solomon grundy, black manta, darkseid, silver banshee, persuader, deadshot, rick flag, mxyzptlk, warp, white queen, live wire, parasite, neutron.
Both shows have stayed away from the batman stuff.