Ninjago abilities analysis and new spinjitzu form
Ok, hear me out. Ninjago has a lot of cool techniques, and all of them seem to revolve (pun intended) around motion of some kind. Outwards, around an axis, upwards, etc.
With this in mind, I catalogued all of the abilities/techniques that characters have demonstrated throughout the show's runtime as well as the "directionality" of those abilities. (This is NOT including elemental powers or "forms"; I classified those in a separate category altogether.) I based them off of drawing upon some kind of positive internal force called the "Ji". A direct connection to this reserve would explain why the ninja could use spinjitzu in S5 even when they did not have access to their elemental powers through Lloyd and the source dragons. Arin also utilizes this force and the outward projectile form of it, jitzu, just without an elemental power to boot. Corrupting the Ji would result in all of the "evil" techniques like shatterspin, and I included a semi-connection to airjitzu since that was how the writers decided to retcon it out of existence. :'(
What I found is that techniques exist for every possible direction of 3D motion EXCEPT somersaulting (i.e. end over end rotation)--maybe this could be the next DR season's special technique? It would add a fast new transportation method across terrain, great for exploring the Merged Lands, and it could lead to some cool combat scenes. Hence, terrajitzu. It would also be a great callback to young Lloyd in S2 yelling "Ninja roll!"--it would work perfectly as the powerup phrase before the gang rolls out!
(Yes, that image is from the Sonic 1 movie. I imagine it would look something like that.)
TL,DR: I expect some new spinners in stores very soon.