Ben 10: Protector of the Omniverse
This is what we have so far:
Ben, Gwen and Kevin's ages will remain the same.
Azmuth will die, which is how Ben gets the Infinimatrix.
Galvan Mark II will then be governed by a council.
There will be a civil war between Undertown gangs which will escalate to World War III (major subplot).
Ben will try to get closer to his longtime crush (major subplot).
The main villain will be someone from another timeline, with vast knowledge of time and space.
The Infinimatrix will be more futuristic and be different from previous Omnitrices.
The voice command feature will come into play more often.
When the dial pops up, not only does a hologram of the alien pop up, but Ben briefly gets a demo of the alien.
It gets most of its power from a mineral named Polymium, found only on Viscosia.
It is universally connected to all timelines, and will notify Ben when a timeline has been destroyed.
Ultimate Alien will be the last canon series in the timeline. Events after the series up to before POTO will be shown in flashbacks.
Azmuth's killer will be a Galvan from Timeline 999 named Zargon, who has vast knowledge of time and space and is jealous of Timeline 999's Azmuth.
Zargon will be part of a bigger alliance (consisting of Ben-21, Zargon and two others), who plan to cause chaos across all timelines by making the negative timeline (a place outside of time and space) the only existing timeline.
Here are a few of the timelines I've thought of. Some may not be numbered.
Timeline 0: An erased timeline, from the first reboot of POTO. This was meant to be Timeline 1, but something happened that changed it.
Timeline 1: Prime timeline.
Timeline 2: Canon timeline.
Timeline 3: A timeline where Ben didn't give up the Ultimatrix for the Omnitrix. This Ben will grow up to become Ultimate Ben.
Timeline 4: Based off the pre-production Ben 10. Same as we planned for the previous POTO.
Timeline 5: A timeline where a World War III sparked after Ben's identity was revealed.
Timeline 21: I think you all know this one.
Timeline 33: Gwen 10 timeline.
Timeline 59: Original Ben 10,000 timeline.
Timeline 60: Generator Rex timeline.
Timeline 88: Max is younger, and never met Verdona nor had kids. Crime rate is very high. Same as we planned for the previous POTO.
Timeline 887: Eon's timeline.
Timeline 999: A timeline where time sped up a billion years. Ben 10: Meta's timeline.
Timeline 2204: A timeline where the Omnitrix sent out a shockwave when it crashed, granting people powers of its aliens (one alien per person). The actual device became obsolete after that (somewhat inspired by The Flash). Ben got the powers of Echo Echo.
A timeline where Ben received the Spark instead of Gwen. Because of his proficiency in using his Anodite abilities, his Omnitrix aliens are mana-charged.
A timeline where Max received the Omnitrix as originally intended.
A timeline where Ben joined the Galactic Enforcers.
A timeline where Gwen left Earth to develop her Anodite powers. The Highbreed managed to destroy Earth.
A timeline where the Omnitrix crash landed far away from Ben, leaving it in the hands of someone else.
A timeline where Ben can transform into mythical creatures instead of aliens.
A timeline where the Omnitrix contained totally different aliens (ones I made up in my childhood).