To be honest, although I like the Netflix shows, I feel like they've already overextended themselves for the characters they are actually using.
Post-Defenders, it would be neat to see Daredevil keep his own series. I personally don't feel that any of the other three Defenders have justified their own second season. You could just keep doing The Defenders every fall and have guest appearances by Luke Cage, JJ and Iron Fist in other series and that'd be good enough for me for those characters.
That wouldn't be reaching Netflix's potential though. They need to expand the cast and world by pushing further out into the supernatural with characters like Blade, Ghost Rider and Moon Knight. Those three could each handle at least one season on their own. Shang-chi would also be a great one to do right now instead of a second season of Iron Fist.
In a few years, when the budget is more reliable, it would be amazing to see Man-Thing. And eventually, the best character to finally "bridge the gap" with the films should be She-Hulk. Give her one mini-season starring characters from both the films and other Netflix shows, then have her become an Avenger. Around 2021, it would be good to see a lineup looking something like this:
Daredevil
Heroes for Hire (Luke Cage, Iron Fist, and Jessica Jones)
Moon Knight
Midnight Sons (Ghost Rider, Blade)
Man-Thing
The Defenders (everybody)
Let villains and supporting cast (Night Nurse, Elektra, The Punisher etc.) get around and you've got yourself a really great thing. With two major teams per year (Heroes for Hire and Midnight Sons) and The Defenders every other year, you also have plenty of room for three solo series.
These should be used to introduce new characters or give additional seasons, but only if they are earned. Probably shouldn't try to go past six series per year ever.
I am completely against canceling Punisher and not giving Elektra her own series. That's stupid considering how much solo source material both characters have.
I really feel like it should be like this.
2018
Jessica Jones Season 2 (No idea who the villain is going to be. Needs to involve pregnancy storyline and Daughters of the Dragon.)
Daredevil Season 3 (Kingpin as the big bad, Bullet, Typhoid, Echo and Bullseye as antagonists. Adapt Born Again and Touch of Typhoid and do Karen Page's death from Guardian Devil.)
Luke Cage Season 2 (Diamondback becomes Coldfire. Atlas and Warhawk introduced as additional villains. We meet Shades' estranged son Victor who also gains superpowers. Mariah Dillard remains the big bad.)
2019
Iron Fist Season 2 - Adapt The Last Iron Fist Story and The Mortal Iron Fist. Orson Randall appears as key supporting character. Zhou Cheng, Steel Serpent and Madame Gao as villains. Danny gets a ****ing costume already!
Punisher Season 2 - Not sure what the plot should be since I have yet to see where Season 1 is headed.
Defenders Season 2 - Adapt Seven Capital Cities of Heaven. Madame Gao and The Hand as one set of villains until the last two episodes when Xao and HYDRA take over as villains. Roster now has Misty and Colleen as full members.
Elektra Season 1: Elektra heads to Washington DC to assassinate the newly-elected Ken Wind after she learns that he's part of The Hand's leadership. Deathlok also appears.
2020
Moon Knight Season 1: Mercenary Marc Spector is sent to fight the Hand over in Egypt and winds up being betrayed by his colleagues in Bushman PMC where he's shot and left for dead upon the altar of Khonshu while Bushman PMC mercs raid the temple. Marc Spector survives and is now out for revenge despite a brain injury taking a toll on his sanity with the default Marc Spector personality being folded into Moon Knight and new Stephen Grant and Jake Lockley personas surfacing all while hearing the voice of Khonshu in his head urging him on to not only recover the priceless artifacts stolen from the temple but also to engage in acts of extreme violence upon his enemies. Marc must defeat Raoul Bushman and his former brothers in arms and track down the lost artifacts so they may be stored in the Museum of Natural History.
Heroes For Hire Season 1: Luke Cage, Jessica Jones and Iron Fist get combined into one series with Misty and Colleen also being main cast members. Rand Industries has bought out Alias Investigations and renamed it Heroes For Hire. Of course the Heroes For Hire are brought on to investigate an AIM facility operated by Dr. Tilda Johnson and her assistants the Carr brothers. Things get complicated when Luke starts falling for Tilda and puts his commitment to Jessica to the test.
Daredevil Season 4: Attorney Larry Cranston knows that Matt Murdoch is Daredevil and is targeting everyone he cares about. He has poisoned the mind of Melvin Potter and set him loose up New York City and driven Matt's new wife to divorce him after exposing her to his fear gas. Adapting the Karl Kesel, Joe Kelly and Ed Brubaker runs.
Shang-Chi Season 1: A young MMA cage fighter in Hong Kong is recruited into SHIELD after it's revealed that his fights were rigged by the Si Fan triad for reasons that he can't even comprehend. It turns out that he's related to most of their leadership and now that he's working with SHIELD as an undercover agent, he must dismantle the Si Fan from within... assuming that he can manage to do so without the ever watchful ex-HYDRA agent Tony Masters catching him. Assisted by two former SHIELD agents (Mockingbird and Lance Hunter), Shang-Chi must choose between loyalty to family and his duty to SHIELD.
Ghost Rider Season 1: After the events of Agents of SHIELD: Season 4, Robbie Reyes is now bonded to Eli Morrow while Johnny Blaze's curse has returned to him. Both hoping to find the man who they feel is responsible for their present situation, they bond over a shared predicament. Johnny takes on the role of Robbie's mentor while Robbie assists Johnny with his revenge upon the man who once critically injured his father-in-law. Drake Shannon's soul must be harvested for Johnny to ever achieve any level of peace.
2021
Punisher Season 3: Again, never seen Season 1 so I can't speculate yet.
Elektra Season 2: Elektra heads to Tokyo to discover who her birth parents are and along the way fights former friend turned agent of the Hand Nina McCabe.
She-Hulk Season 1: After being injured and saved by a blood transfusion from her cousin. Jen Walters becomes a super-strong lawyer in a legal sitcom that's basically Ally McBeal with superpowers. She needs to juggle her daily life with the fact that her skin is now green and she manages to break everyday items without trying. And somebody named Mary McPherren now wants to fight her just to prove she's stronger.
Blade Season 1: When a woman named Rachel Van Helsing informs the Nightstalkers that Vlad the Impaler is the leader of all vampires worldwide, Eric Brooks doesn't take her very seriously and believes that she just read some Bram Stoker and engaged in a crazy delusion because her last name was Van Helsing and ships her off to see Doc Samson. It's a story too unbelievable for even a team of seasoned paranormal investigators, despite the fact that two of them are vampires themselves. Only when Eric learns that she's telling the truth does he begin to learn the truth about his curse as one of the undead and his connection to Dracula will change his life forever. Based heavily on Marv Wolfman's Tomb of Dracula and Dan Chichester's Nightstalkers.
Defenders Season 3: Adaptation of Shadowland. Matt Murdoch has now joined The Hand after suffering multiple unspeakable tragedies only to learn that he is a Black Sky which makes him a vessel for The Beast. It's up to the Heroes For Hire to team up with Elektra, Punisher, She-Hulk and Moon Knight to save him from himself.
There you go. What I'd do. This is assuming that Iron Fist and Defenders both get renewed and another network won't take Ghost Rider and Blade series.