darkSpyro

Cuttthroat Carnival is the longest quest available for each...

Because there are no Trap Team missions or enough Light/Dark themed levels in the main games to add to them - it's just Midnight Museum and Sunscraper Spire,which being AP levels warrant being the 22h missions but there might be coding issues when they try to add the other ones. They're probably waiting for the next game which might have more than enough areas to make missions out of.

They don't have any of the elemental adventures, not just the longest. It's annoying.

Though they could always repurpose unused levels as Dark and Light - Monster Marsh was kind of Undead,kind of Dark since it was in the middle of the night, and the Waking sacred grounds in the 3DS levels,though actually Golden Desert model rehashes, could be Light-Themed. But it's still kind of a stretch,they must be waiting for more obvious chapters.