Okay, so this is far-fetched, but listen to this theory I have.
So, the prequels intended to parallel the OT, mirroring Luke's ascent to the Light Side of the Force with Anakin's ascent to the Dark Side.
I found this film to mirror Episode IV in a ton of ways.
3 young heroes; 2 males and a female. 1 is clearly force sensitive (Luke/Rey). 1 exhibits abilities of force sensitivity (Leia/Finn). 1 exhibits an extreme amount of skill/luck with conventional fighting (Han/Poe).
Two of the heroes are revealed on a desert planet (Tattooine/Jakku); one of these is a local and one a pilot visiting. One is introduced on a ship (Leia/Finn), although Finn is a little weak on this point as Leia never even goes to Tattooine.
Before I continue, we also have a new planet/weapon with a vulnerability, Kylo Ren as a vader-like figure, Snoke/Sidious, Hux/Tarkin commanding the installations, tractor beam capture on the MF, people coming to Solo for debts, Solo being focused on himself at the moment in time (originally a smuggler/smuggler again), develops into a pure hero later on, destruction of entire planets as a form of genocide, New Order as contingency of the Empire, infiltration and sloppy escape from the planet/weapon, securing a computer terminal in the base and then alerting the enemy, mention/depiction of a trash compacter as a means of death, and many many more.
One force sensitive is explicitly told they are so (Luke/Rey), and they are also the desert planet local in the last point. The other force sensitive is not explicitly revealed (Leia in ROTJ/Finn) and Maz alludes to Finn being FS by telling him to use Luke's saber, even though a non-FS would probably lose to blaster fire. She even insists he use it. The final hero (Han/Poe do not appear to be FS, but perhaps seem to be influenced by it. Let me explain:
Solo and Poe are both expert pilots, and display proficiency with small arms. Solo feels extremely confident with a blaster, and very much so with Chewie's bow as he is surprised by the firepower. He is cynical about the Force and sabers in every film, even when he is admittedly in awe of the Force himself in this one. Poe has much less on screen time, but mirrors much of Solos persona, down to the leather. When denying Ren he acts in the same cocky manner and refuses to cooperate when captured until the last of his will, just as Solo is bound in carbonite and sacrifices himself in an attempt to stop Ren.
Both are spectacular pilots, and this is much of the focus made on these characters. Both save the day with their ships in IV when Solo shoots Vader off of Luke's tail, and when Poe uses his X-wing to save the Resistance forces and his friends at Maz's base. Both of these attempts displayed almost force-like assistance at the very least, outclassing every single enemy and allied craft in the battles. You can probably see where I am going with this.
In IV, Solo is very rough on the outside, and does not respect Kenobi openly until after his death. It is clear he valued Kenobi as a mentor, much in the same way Luke did, as he even named his own son Ben. In IV Kenobi sacrifices himself to Vader. This is in order to give the heroes a chance to escape on the surface, but here is what I am getting at:
When Kenobi turns to Luke, smiles, and lays down his weapon, Vader strikes him "dead." Only he isn't dead. Kenobi mentions before their duel something to the effect of:
I have become more powerful than you could ever imagine. Even if you kill me, you cannot defeat me.
This is because Kenobi was completely one with the Force, and was able to become a force spirit. When he died, his body vanished into pure Force energy. This is what allowed him to not only ensure Luke's success with new powers, but to manifest as a ghost and talk to Luke inside his own head. (This is all canon.)
Solo sacrifices himself at the end of this film. While not conciously one with the force, he has exhibited the same impressive abilities and most of all, luck. If we consider both him and Poe to be experts that simply manifest the Force in their areas of expertise without being aware (recall that Leia only discovered she was FS because Vader was her father), perhaps both have been using the force without knowing it, or are intrinsically as pure-hearted as the other heroes as a result of FS. So, what if Poe/Solo are actually Force Sensitive just as everyone but Finn clearly is? if Leia could've gone forever without realizing it, could Poe/Solo not as well; especially due to their appreciation of small arms and airborne combat?
If a FS can go their existence without realizing it, yet channel the Force into their proficiency in combat, perhaps consistent honing of these skills could be the equivalent of Jedi training. Why would a FS need to become a Jedi to become one with the Force, when Sith can become Force Spirits as well? Jedi and Sith are both religions that worship and utilize the Force. If one becomes one with the force by simple experience - Jedi or Sith training, there is no reason to believe that either of the religions are necessary to use the Force- just that they are methods of becoming one with it.
The Force is not objective. It is a raw power that can be harnessed. The "Sith" in this film use neither the Darth moniker, nor mention the Sith religion at all. They are likely not Sith lords, but simply a new order of Dark Side users. The Rule of Two is even broken (Knights of Ren), and Snoke prefers Kylo for his instability and rage, vs. Vader being compliant. That does not line up with Sith ideology. Anakin was groomed because he was easy to influence, and powerful.
So, let's assume that Solo/Poe are FS and benefit from the Light Side through their good deeds and alliance with the (few) Jedi. In IV, Kenobi is at a peak of wisdom and beneficent power. He is at one with the Force through the Jedi religion. Solo in this film has not only witnessed the type of sacrifice that creates a force spirit, but tends to model Kenobi in this film as the Master fostering the young heroes and helping to rescue them. Luke is now the Jedi Master and is in isolation, like Yoda. He is where Rey is to receive advanced training, rather than being along for the beginning as Kenobi was. Kenobi gives Luke his saber, and he makes the same gesture to Rey with his blaster pistol and tells her to train.
Kenobi/Solo(VII) both are leaders of the infiltration of the planet/weapon in IV and VII respectively. When Kenobi confronts Vader, he sacrifices himself to try and save everyone else. His actions allow him to guide Luke to success and win the war. When Solo confronts Kylo Ren, he sacrifices himself to try and save everyone by appealing to Ren how no one else can. Both accept death as an option to attempt to make the world right again. At this point in their lives, they have done amazing deeds out of the pureness of their hearts. The final sacrifice of Kenobi allows him to consciously become a force spirit. So what if Solo's final sacrifice and history of selflessness + a potential proficiency in unique Force use/channeling of the Force make him one with the Light Side as well?
What if Solo, who did not die onscreen, but fell, succumbed to death and his body vanished offscreen? Then the Force Spirits of past Jedi, such as Kenobi, contacted his spirit and taught him how to become a Force Spirit as well? Remember, of all people, ANAKIN SKYWALKER became a Force Spirit despite his tyranny, simply because he SACRIFICED himself by killing the Emperor to save Luke in VI.
If Solo is this films Ben Kenobi, I think he is not quite gone. We may very well see or hear his spirit in the films to come. What if Solo was an unconscious Force user, and now a Force Spirit?
Additional support comes from Kylo Ren himself. Would Solo being FS as well as Leia not support the seemingly raw power that Ren utilizies, that is more powerful and wild than Anakin ever seemed to be. His only weakness seems to be the Light Side. Perhaps his insane power is a combination of 2 FS parents.
Solo becoming a martyr for humankind was the ultimate sacrifice he could have made. If he was FS, he could have easily become a Light Side Force Spirit if such a sacrifice makes one complete with the Force, as with Kenobi, Anakin, and Qui-Gon Jin. One final point is that for powerful Force users, they typically do not die unless they cause their own demise. This is true of Kenobi, Leia, Luke, Vader, Finn? and Palpatine. Solo as a mere mortal (supposedly) has endured trials of much the same kind, yet found it just as easy to survive, as if guided by the same safety the force brings to one's current destiny.