Exploring More of MKUltra
The MKUltra experimental program and its employees played huge roles in Season 1. Falling under the purview of the U.S. Department of Energy, the Hawkins National Laboratory is the hub for Upside Down activity, housing the rift to the dark dimension, and also, it was where superhumans such as Eleven and Kali were engineered. Even though the Hawkins lab was shut down at the end of Season 2, that doesn't mean the entire MKUltra program is done.
Season 3 can explore more test subjects like Eleven and Kali, both good and evil, and maybe even look at new ones currently being raised as soldiers. With Brenner said to be alive, maybe there are other programs similar to MKUltra or even extensions of it the Duffers can expand on. Afterr Kali and Eleven exposed themselves to an ex-worker from the Hawkins lab, Ray Carroll, and nearly killed him, maybe MKUltra could send more operatives after them. These sinister elements work pretty well so Season 3 ought to maximize on them as this season barely touches on such powerful humans as villains.
Evolving the Tone
Stranger Things needs to evolve in Season 3. So far we've gotten a lot of jokes, with Season 2 really forcing the humor in at times (like with Dustin joking when the team was strategizing against the Mind Flayer). We've also gotten a lot of romance in love triangles with Dustin, Max, and Luke, as well as Steve, Nancy and Jonathan.
All this does is make this season feel like the Duffers are trying way too hard to recapture what worked well in Season 1. As much as it's awesome to connect with that old spirit, the new narrative has to feel organic. It should mature with the kids in Hawkins and find a suitable voice, one that's comfortable in its own skin. This new core essence can still keep the themes and tones of old while relaying them in a different manner. The Duffers have to be fearless with change, maybe even diving into more straight-up horror territory next time around. With Season 3 already in the works, the duo would be smart to evolve their vision in order to prevent things from going stale.
Now streaming on Netflix, Stranger Things Season 2 stars Winona Ryder, David Harbour, Finn Wolfhard, Millie Bobby Brown, Gaten Matarazzo, Caleb McLaughlin, Natalia Dyer, Charlie Heaton, Cara Buono, Matthew Modine, Noah Schnapp, Joe Keery, Sadie Sink and Dacre Montgomery.