These ones were also not as barren; even if they are, however, some of these things. . . Dang!
Sons of Garmadon - Was originally going to act as a continuation of Hands of Time, but luckily, that wasn't done. As you can see, S8 was a big redemption for Ninjago after one of its weakest seasons, and there was no better time to implement the new designs. If they'd done a continuation of a weak season, things would be blown to heck.
Mr E., *surprise surprise* was going to be revealed as Echo Zane! There's an animatic, too, look it up. It never came together, however. I've always not known how to go about this theory, ya know? Like, I don't exactly know how plot relevant this would be, and Echo Zane hadn't appeared since Skybound and everything had been reversed. So he'd still be at the Lighthouse, and although he's got a good villain motive, likely wouldn't know he has it. And thinking about it now, did Jay come across Echo Zane when he returned to the Lighthouse between Seabound and Crystalized? He must have. Yet again, another plothole formed by Crystalized *sigh.*
This one's weird. So. . . you know Hutchins? He was in the first few episodes, and died in the palace fire. So, according to the wiki, he was going to return as a red herring (like, some kind of clue or misleading thing according to google) for the Quiet One. So, how would that be used? It never specifies. I suppose it's elaborated more somewhere, probably by Tommy, and I'll probably update this if I get more info. But that would be interesting-- and kinda dark.
Hunted - Didn't get much here, except oh! The tables have turned! Garmadon resurrects Harumi! Boy, honestly though, I'm glad they didn't do this. It would be kinda cramming things in at that point, and the whole thing Harumi had going would've been ruined. Uhh, much too early anyways. *Cough* Crystalized *Cough*
March of the Oni - In the finale, and this is boutta sound bizarre, Garmadon flies away on the Firstbourne with the four golden weapons, and creates another realm as the FSM did. WHAT?! Why- huh- wha? How would he get the Firstbourne to comply to him? He's an oni and it's a dragon! They'd probably fight to the death! And the first shenanigans with the golden weapons have been blown to heck, and even though Garmadon can't remember the mega weapon, something tells me he wouldn't want to try again. And he is more oni and is repellent to creation, not to mention. None of this would work. Maybe he got turned into Sensei Garmadon? But even then, he'd probably stay with the ninja and stuff. I can't even wrap my head around this. . .