We know that season 3 of Arrow wasn't the best of all and being honest, for me was the worst of all. The writers are trying to give a better season than the other, and in my point of view of what I see that they are going to bring to the season is going to be freaking awesome!
But just for make sure I'll give some ideas that will make a future season better...
What we need to see!
1. Continue the story of Oliver's son
This happen in a very quick way when Oliver meet again his ex girlfriend, but the thing is that she have a baby that is of Oliver. This can be a good story to explore and something that many of us want to watch.
2. The relationship between Oliver and Diggle
Diggle said that he lost the respect that he have for Oliver after he was a member if the league of assassins and kidnap his wife, it will be very interesting to see how the relationship between them change and if they are able to work together.
3. The Huntress
We don't see Helena Betinelli this season, but she has a great story behind her, that open many doors for a hole season, but the real reason that she is very important is in the next point.
4. Lady Shiva
A lethal weapon without guns, this lady has train many heroes and villains and some say that she can beat Batman in a one on one combat, I have no doubt that she can be a fantastic villain in a future season of arrow, and can fir perfectly in almost every story line, I wish that some day she can be in arrow.
5. The Atom - Palmer Technologies
This character is one that I think have more potential, not only for the suit, or his story with felicity, the real potential is Palmer technologies, the former Queen consolidated. That's the real potential, a fight against Oliver Queen for the company . I know we saw that already but it wasn't what we want.
What we don't wan't to see
1. Malcolm Merlyn
At the first season it was a incredible villain, it has a perfect story and the reason to do what he do, but now I think is just there because they don't know what to do with him, I think is time to let Malcolm rest and bring him back when is the right time.
2. Leave in peace a Thea
Thea is that character that happens everything to her, she was kidnap, she dies, she was in drugs, I'm not saying that don't put Thea on the show, just make that the other characters get into trouble too. She deserve a break.
3. Stop making Laurel get away from Oliver
Since Laurel dress as the black canary she haven't talk to Oliver so much. Both have a past, and are friends, they relationship have to get more explore just like in season 1. They have to make us feel that they are connected or at least they now they are partners.
4. Make Felicity understand what is right or wrong
She hasn't do any sacrifices I mean real sacrifices, she only cares what is important to her and don't want to listen the truth, I think it will be a good idea changing papers with Thea, to understand what to be a hero means.