Christian

Wonder how Oda chose the Gear system. Is he a car guy? Because back when OP started, 5 gears were what 99% of cars maxed out at. Then 6 speeds became the norm not even a decade later. So Gear 6 is absolutely a possibility, but who knows what that might release. A full personality takeover by Nika? "They will meet again."

Just the opposite. This will be Luffy's redemption after failing to save Ace. There's no reason for him to lose Garp, too. Really wouldn't fit the narrative, as he's already grown after experiencing the death of Ace. What's another death of a family member going to teach him?

Would be interesting to see if Xebec used Haki to infuse his soul/will into Blackbeard, like how OG Joy Boy infused Haki into the robot.

It's pretty obvious now that Blackbeard is holding his father's will/soul somehow, and that is mostly steering the ship, only losing grip when Blackbeard himself gets scared or hurt. That's when you see flashes of the true Blackbeard, enslaved against his will. Setting him up to be a tragic character that may be redeemed (freed or sacrificed) by the end of the great war.

50/50 shot the final war will be like Marineford, but Luffy will save Dragon vs losing Ace. Lots of parallels to earlier in the story, since OP was originally supposed to end long ago.