Now for Supergirl season 3 and Flash Season 4 along with the main villains are to be dark toned so that CW can for god sake stop being so lame and start feeling the need to get serious, real serious and not keep acting so ignorant with their own self interest in defiance of such pride. Because that way the shows won't be so irritating with the characters and the episode plots.
In Supergirl Season 3, the original Silver Banshee that Superman fought in the New Earth comics is to be introduced as the main antagonist with her real name addressed as Agatha, Fiona, or Michaela McDougal instead of Siobhan so we're not confused with Italia Ricci's character who is due to return at somepoint for Supergirl Season 2 for redemption.
As the main antagonist of the third season, the Silver Banshee McDougal's plot is to tear Kara's normal and superhero life apart in the process of killing her sister Alex, her mother Eliza, or her father Jeremia to make her and Superman suffer for their interventions with her affairs and Cadmus' plans. Also the Silver Banshee will gain authority as Project Cadmus' military leader under Lillian Luthor's authority incase she and Cadmus will still remain active after season 2 since there is more to feature from the organization and with their help, McDougal will turn two people Kara looks up to, even as Supergirl, against her and two of them that would impact her life the most are Lucy Lane and Lena Luthor. For Lucy at somepoint during the third season, the Silver Banshee would expose her to physical and psychological trauma by deceiving her into believing that Kara dragged James out of her date over the Indigo crisis just so she gets him to be her boyfriend and that she is a real threat to Earth and after driving Lucy over the edge, McDougal will inject her with Supergirl's blood and provide her with the costume to keep her identity safe and has Lucy become Superwoman and as an agent of Cadmus who will lash after Supergirl for ruining her relationship with James and wipe out as many aliens as possible. Now for Lena , McDougal is sure to go easy on her since she's Lillian's daughter and has issues with her brother and family just like the Banshee. She will either wait for Lillian to perish in Supergirl's next conflict with Cadmus or take advantage of the situation and be indirectly responsible for it so that Lena will come to her terms and by taking over her mother's position as chairmen of cadmus, Lena will also accept samples of Supergirl blood and become Ultrawoman soon as Cadmus' fate is at risk. In the season finale, McDougal will unleash Doomsday on Superman, Martian Manhunter, and the rest of the DEO if Jonn's position as leader will still stand after the second season while the evil, vicious, and volatile Silver Banshee herself will face off with Kara and Siobhan in an epic final battle out in the fields where Supergirl made her arrival on earth and Smythe is the one who is to kill or pulverize and apprehend McDougal before Supergirl goes to help Superman and the others defeat Doomsday.
I know, rough but Supergirl has been light toned and it really lacks the more serious hostile threats which is why they should have the series feature both Silver Banshees from the New and Prime Earth comics so that things can get more interesting with Siobhan Smythe being Kara's best friend and McDougal as the girl of steel's arch enemy and incase things get too much for us, CW really needs to lighten the load of drama talking characters before things get too irritating. Besides McDougal's cause for becoming the most aggresive foe to Supergirl and Superman as the Silver Banshee, her origin story is what makes her a suitable fit on being the threat who delivers a critical blow to the last children of Krypton and to why CW shouldn't dawttle with anything or anybody else in the comics until they give us the potentially serious characters that we want.
Now for Flash Season 4, while Zoom is confirmed to return to the Arrowverse as the Black Flash, he is to serve as the main antagonist once again for the fourth Flash season so that he can finally drive Barry into killing people and by having Weather Wizard, Mirror Master, Top, Tarpit and Rainbow Raider rob him of all the pride that is keeping him stubborn from being discipline and by leeching Cisco of his powers and with the Rogues helping him overwhelm Barry with the most painful physical and psychological trauma and Bivilo's pathekinetic power to keep Barry angry, their plan of making him kill hundreds of normal criminals throughout Star and Central City within the next crossover between Flash and Arrow and once it's successful that with Barry later subdued and put behind bars for manslaughter, Black Flash is to lead the Rogues and all remaining Earth 2 metas into wiping out all the dispatchable cops in the CCPD with Mardon killing Joe or Captain Singh or Cecil in case Savitar kill's the detective in Season 3 while Tar Pit kills the two thugs that Iris and Barry kept him from punishing for swindling him on his life the moment they tried to kill him like selfish jerks. And if CW doesn't have Caitlin betraying Barry and Team Flash as well as leaving the team as Killer Frost, they are to make sure Zoom kills her for betraying and vexing him this time without anyone stopping him and let Julian live to tell Barry about the fall out and they are not to keep making her stay over their interests and obsession with the nerds because Barry needs to stop worrying so much like a stubborn 11 year old minded wimp and start embracing the worst of his losses and humiliations because that's how he keeps letting more people die and rather than trying to end a war before it starts he is to fight it like a man and in the season 4 finale, he and Jay are to face Black Flash, the Rogues and his arch enemy's army of metas from Earth 1 and 2 without using Star Lab's multidimensional shockpulse in Central City Park with Vibe, the Legends, Team Arrow along with Supergirl, Superman, and Silver Banshee Siobhan Smythe accompanying them in the ultimate showdown and finally Barry and Jay are to lead Zoom to his house where he and Eobard Thawne murdered his parents and by subduing the monster of his capability to stand, they are to keep him restrained in the middle of the house so that Siobhan can destroy Zolomon once and for all with the intensity of her sonic screams. Then after winning back Central City, Barry and his friends are to be rewarded by the Mayor for their efforts of stopping the uprising and Valerie Perez is to take Caitlin's position on the team as their medic.
Now for Arrow season 6, CW is to have Bruce Wayne/Batman and his allies make their debut in the Arrowverse for the first time and have the Riddler act as the next season's big bad because with Starling City not having brought crime and corruption down easily isn't just because of Team Arrow focusing most of their time on the main threats but also because most of the criminals in the city lack the intention of changing their criminal ways because of their minds lack the mental capacity to learn which is why Riddler should work and with Jim Carrey reprising his role from Batman Forever, he should help lighten up the mood of the sixth season with plenty of crazy and wild humor and boost the ratings too. Also for the other major villains for Team Arrow and Batman to face off with involve Bane, Electricutioner, Hyrax and her organization the Eden Corps. Afterall Batman and Oracle have been referenced and mentioned so there is no point on having Andrew Kreisberg and CW hold back any longer from including them and the other characters from the comics into the Arrowverse which is why season 6 of Arrow is the perfect time to do so. For those of you all in favor of this article of suggestions please convince CW and Andrew Kreisberg and the producers of the shows to use all these characters and information in this post for Supergirl season 3, Flash season 4 and Arrow season 6 before they make any further major announcements. The rest of the recommended villains and what rank they are to be are right here in this chart.