Most people had a dislike for season 4. Personally, I didn't mind the fourth season at all. I loved the season finale. I liked Damian Dhark, Vandal Savage, Lonnie Machin, and Baron Reiter. However, there are some changes I wouldn't mind adding to this season.
Changes I Would Make For Diggle's Role: In the fourth season, Diggle took Oliver's advice and became a masked vigilante known as Spartan. An antagonist for him this season was his own brother Andrew Diggle which I don't mind at all. It was a shock to discover that Andy was still alive because we all thought Floyd Lawton AKA Dead Shot killed him. I would prefer if Dead Shot was alive and he had been by Amanda Waller as well as A.R.G.U.S to infiltrate HIVE by pretending to be one of Damain Dhark's ghosts. In the third episode, one masked Ghost gets the drop on Diggle and has him at a point-blank range with a rifle in his face, however he doesn't shoot him and flees the scene. I know that it was Andy, I would prefer Dead Shot was still alive. I also prefer if we saw some flashbacks based on one of the issues of the Arrow comics where Diggle goes the hunt for his brother's killer and attacks a guy whom he believes to be the killer after stealing a file from the SCPD. I don't know what the issue is called, however the guy mistook Diggle for a cop. After Diggle shot Andy, I would want to see how Carly would react to John shooting his own brother as well as her husband. I bet that would create a lot of drama for John this season and be one of the reasons to why John decides to leave to join the Army again.
Make Damian Dhark A Bit Like Theo Galavan: I know this may seem odd, however, elections for mayor did happen in the second season of Gotham and the fourth season of Arrow. In Legends of Tomorrow, Damian used Eobard Thawne's Sphere of Destiny to make himself the mayor of Star City. I would prefer if Dhark was trying to run for mayor while under the alias Kenneth Bender. Dhark can still manipulate dark magic from the totem (which was awesome by the way), however, he becomes a bit like Theo Galavan by manipulating events to make himself look like the hero that Star City deserves. Dhark hires Lonnie Machin AKA Anarky to start killing people and be like one of those serial killers that appeared in Dexter while leaving his symbol behind written in his victims' blood which gets Lance and the media to nickname him as Anarky. Dhark is only using Machin to provide bad publicity for the city council in being unable to deal with the crimes in the city. I was thinking Machin would be an antagonist for the first half of the season and then Dhark eventually betrays Machin for kidnapping Jessica Dansforth's daughter when Jessica is running against him and Oliver for mayor. Eventually Dhark gets sent to prison in a trial because of Lance testifying against him and another person becomes the mayor while being under the influence of H.I.V.E's pills (just like how Ruve used it against Alex Davis). I also found the part where Damian Dhark is nuking the entire world to be pretty cool too. Oliver still kills Damian while being the Green Arrow during the season finale and Lance is still forced to work for Dhark under duress.
Changes I Would Make To Felicity's Role: Everything is still the same with Felicity being with Oliver and ending her engagement with Oliver after learning about William. I also don't find Felicity being paralyzed and then being able to walk again because of a chip designed by Curtis Holt, however, I woud prefer if Ray Palmer's brother Sydney Palmer appeared on the show and tried to take Palmer Tech back from Felicity feeling she is unworthy to protect his brother's legacy. I also don't mind at all about Donna Smoak appearing as Quentin Lance's love interest and Noah Kuttler AKA The Calculator being Felicity's father. Speaking of Sydney to be honest, I would prefer if he took over Palmer Tech after Felicity was fired and be the one supplying weapons to Tobias Church in the fifth season while replacing Janet Caroll's role. I got the idea from Gotham Underground where Tobias Whale became the new CEO of Kord Industries and Ray Palmer was originally intended to be Ted Kord. I bet that would create more tension between Ray and his brother just like in Legends of Tomorrow.
The Huntress Returns: I would prefer if Helena Bertinelli returned again as the Huntress and this time joined the Suicide Squad like she did in the comics. I like Huntress and I feel she should come back and be given a chance for redemption.
As For Who Dies: Very recently I read something about someone saying that Arrow was right to kill of Laurel Lance and I find that to be harshed. Like the other fans, I was pissed to learn that Laurel has been killed off. I feel that someone irrelevent to Team Arrow but to important to Oliver should've been killed off. Sadly, it would be Samantha Clayton, the mother of Oliver's child. That would mean William would have to live with Oliver and I would love to see how Oliver would act as a parent while Thea is being an aunt. That would be a motivation for Oliver to kill Dhark at the end of the season as the Green Arrow and go back to killing for the fifth season feeling that William wouldn't be motherless if he hadn't killed Dhark sooner when Dhark was escaping from prison. Oliver going back to killing in the fifth season would piss off both Laurel and Thea.