There's clearly already a good amount of shared structure between Death Stranding and Metal Gear Solid 5: The Phantom Pain, the last game in the series developed by Kojima Productions. However, with as much DNA as these two titles share, there is one feature that isn't common between the two that Death Stranding 2 should change.
Specifically, this would be the recruitment system that drives much of MGS5 and allows Venom Snake to build up the Diamond Dogs and empower his research and development systems. So, given that unlocking and fabricating gear is an important part of planning deliveries in Death Stranding, the same mechanic could be better refined in a world that has fewer resources and people to pull from.
Given the systems present in Death Stranding, as well as the overarching narrative of connecting the world and connecting with others, any character interactions should be given the chance to have positive effects. Even the incentive not to kill the Mules and Demens that try to kill or stop the player could be maximized on with the ability to recruit them, though there may be a give and take with some of them. Then, aside from the new ways that this could allow for NPC interactions, recruitment could completely remake the development of new gear in Death Stranding 2.
The current system for gearing up for a delivery in Death Stranding already feels like it's been stripped straight out of MGS5, with a blank void to prepare weapon, vehicle, and additional equipment loadouts. It's a great way for players to get ready for missions and adventures through Metal Gear Solid's open world, and translates perfectly into attempting to travel through dystopian America. However, one benefit that MGS5 has over Death Stranding in this way is that the player has more control over what they can bring thanks to the ability to research and develop their own gear.
This added level of customization makes each player's trip through Metal Gear Solid 5 as a personalized Venom Snake unique, as everyone will decide that different options are important. Missing out on certain loadouts by the end of the game can be disruptive, but overall, the ability to invest in items is a huge part of MGS5. Then there's the recruitment feature that fuels this entire system, by picking up enemies to bring onto Snake's side and gain their benefits to unlock better equipment.
On top of a newly revamped R&D system, being able to recruit enemies in Death Stranding could give players an added incentive to intentionally head into Mule and Demens territory. There's currently the benefit of being able to find gear and materials within those areas, but there is a point in the game where it becomes easier to simply find or make alternate routes around the enemies. So, giving players the ability to run into these enemy camps and pull a handful out to be recruited into Bridges could make the world of Death Stranding feel more alive and like the player's actions have more effect.
One change that should definitely be made to how MGS5 handles this system, however, is the removal of the Fulton recovery balloons that makes capturing enemies very easy. Instead, players should have to physically take Mules and Demens to different facilities, possibly to a specific few that have the ability to rehabilitate these enemies, making each recruitment a much more intimate encounter. Given that the entire narrative of Death Stranding involves connecting Sam to the other characters around him as much as connecting the United Cities of America, having the chance to rescue people would really help drive those themes home.
Throughout the marketing leading up to Death Stranding's release, and within the game itself, Kojima Productions made it perfectly clear that the themes of the narrative are meant to be focused around making connections. In this case, it comes off as strange that players are told to leave the Mules behind due to them becoming addicted to delivering and impulsively trying to steal cargo. Players really should be given the option to help at least these people by taking them back to a city and working them through their addiction before transitioning them towards reintegrating into society.
This is a bit of a heavy topic for a game to take, but Death Stranding's best moments come from jumping into really tough situations, like Higgs' backstory and the Chiral Artist's relationship with the Junk Dealer. The same situation might not work as well with Demens, considering the ideological difference there not being something that can be so easily handwaved with a "because video game" mechanic. However, including these enemies can open up for new options that only some players might even see by the end, but could have a huge impact on the experience and perception of the game world.
Allowing players to recruit enemies could open up for something that MGS5 delved slightly into, but never really got the most out of, outside of a few required missions. An additional risk and reward to consider with taking ex-terrorists like Demens especially, could be the opportunity for these enemies to betray the player. This can either cause an upset that the player then has to head out to and address, or create an entirely new narrative within Death Stranding, where Sam is tasked with finding this person and bringing them back.
A character that is more prone for betrayal as well could give an incentive for the player to kill them, even with every system that currently marks that as the absolute last option that should be taken. So now the player chooses, kill a traitor for the greater good, because they're too much of a risk to be left alone, or try to reach out to them again with the possibility that they could cause more damage. This is exactly the kind of tough choice that Kojima Productions is known for forcing into its narratives, but could have an even stronger effect by making the decision completely up to the player.
Death Stranding is available now for PC and PS4.