Luffy's awakening = transformation into a "monkey man”-esque form, taking after Nika’s silhouette (pay attention to the spear-like weapon he’s wielding) and Sun Wukong, allowing him to form a weapon using his awakened powers resembling that of Sun Wukong's Ruyi Jingu Bang.
I’ll list out some important sources to start this out. Take a look at Gear 4 transformations into Snake man, Bounce man, and Tank man. Now, refer to this source about Sun Wukong’s 72 transformations and most importantly his Ruyi Jingu Bang, a magical staff that can change its form/shape at will he received from Ao Guang which is used to defeat a dragon king. If you read further down, you can go as far as to argue that the the “phoenix-feather cap” he received from Ao Guang has some resemblance to the reoccurring Straw Hat theme throughout the story. Perhaps, the giant Straw Hat in Mariejois is that of Joyboy's and that scene of Imu in front of it with Luffy's Wanted Poster is of him making the connection between the two. According to Doflamingo, once revealed, this treasure (implications behind the Straw Hat) is capable of shaking the world at its core and ushering in an era of chaos which may refer to the destruction of Fishmen Island that's predicted by Madam Shirley. This is a well known Chinese folklore all easily accessible online and I think this may be where Oda drew his inspirations for what’s going on in One Piece right now.
I speculate what sets apart Luffy’s new upgraded form (5th gear, his awakening or both) from others is his ability to transform into a monkey man and wield a weapon formed using his newly awakened powers like the one Nika is seen holding or Sun Wukong’s Ruyi Jingu Bang. The idea is this form would shake off some of Gear 4 limitations such time limit, can't walk only bounce (Bounce Man), indefensible while attacking (Snake Man), only able to defend (Tank Man). Luffy will now be able to wield and fight with a weapon that can expand and coat it with Haki, a combat tactic we have not seen before from Luffy apart from foreshadows we can speculate from Nightmare Luffy (Thriller Bark) or him wielding the Nidai Kitetsu from earlier in this arc. The key is that his Gomu Gomu no mi has been awakened. Luffy can now manipulate his surroundings like he does with his own body and the ability to wield and form something like a Ruyi Jingu Bang, reducing bodily impact during combat. This is just one of many benefits of Luffy’s new form + awakened power. I predict that Luffy will use this new weapon (or this may come in the form of the huge Katana on Onigashima) and Monkey Man to defeat Kaidou very similarly to how Law defeated Big Mom, impaling him to the ground.
I think my theory really stands out among the post-1043 theories out there so far because it burrows from other already existing theories and improves on it with all the details while staying within the bounds of how Oda have revealed and connected things together in the plot. I don't think it's some wild secret Oda's revealing "it wasn't a gomu gomu no mi in the first place." As of now, I am not on board with Luffy’s fruit being anything other than the Gomu Gomu no mi. I'm willing to believing it may be something along the lines of Nika Nika no mi but definitely not Resin (as resin can be a conductor of electricity and that directly conflicts with Luffy vs Enel's plot based on scientific facts regarding resin). This whole Monkey man theory still works with Luffy still being a rubber man.
This also leads me to believe that Luffy may be or wield one of the 3 Ancient Weapons mentioned in the story, Uranus. Pluton is a ship of mass destruction that Franky burned the blueprints to after hiding it from the World Government. It's been well established Shirahoshi is Posiedon. But, we don't know much about Uranus yet. I believe Luffy's awakening unlocks the Uranus in him or his ability to wield it. This is why the World Government is so cautiously keeping tabs on the Straw Hats and especially Monkey D. Luffy. Now that he's unlocked his powers to resemble Joyboy's (confirmed via Zunesha in 1043) in his time and WG discovering everything that transpired in Wano (through the other CP0 agent who's currently witnessing all this), the plot thickens. There has been some theories that Momonosuke is Uranus based on his reaction reading Oden's Journal or that Uranus may be the large katana on Onigashima that Luffy will be able to eventually wield through his awakening, manipulating it to his liking to defeat Kaidou. That would also make for an epic ending to Wano.
Lastly I'll leave you guys with this regarding Journey to the West from Wikipedia:
In Journey to the West, the monkey king Sun Wukong obtained his Ruyi Jingu Bang, a magically-expanding, gold-ringed iron rod weapon, from Ao Guang. This weapon was originally a tool for measuring the depth of sea water used by Yu the Great in his flood control and treatment efforts; hence its ability to vary its shape and length. After Yu left, it remained in the sea and became the "Pillar holding down the sea", an unmovable treasure of the undersea palace of Ao Guang.
One of Wukong's senior advisors had told him to seek out the dragon-king in order to get a powerful weapon befitting his skill. In the dragon palace, he tried out several kinds of heavenly weapons, many of which bent or completely broke as he wielded them. Ao Guang's wife then suggested the Ruyi Jingu Bang, stating that some time prior the iron rod had begun to emit a strange heavenly light and that she believed the Monkey King was destined to obtain it. When Wukong neared the pillar, it began to glow, signifying that the Monkey King was its true owner. It obediently listened to his commands and shrank to a manageable size so Wukong could wield it effectively. This awed the dragons and threw the sea into confusion, the Monkey King having removed the only thing controlling the ebb and flow of the ocean's tides. In addition to the magic staff, Wukong also forced Ao Guang to give him other magical gifts; including golden chain mail, a phoenix-feather cap, and cloud-walking boots.
Credits to itzbrianfosho
