Malia wasn’t in the show’s original plan. Jackson was going to be Peter’s long-lost kid. That was part of why the scratch on the back of his neck from Derek started giving him flashes of memory of the Hale house in S1, feelings of familiarity, and why they went into detail about how he was adopted. It’s also endemic to some of this storyline in S2. Meanwhile, Peter thinks his children were all burned to death in the fire.
When the actor for Jackson left the show for Arrow, they didn’t want to give up the “Peter has a long lost child” story so they shoe-horned Malia in instead.
Meanwhile, part of Malia’s arc also came in from a different place. Since they lost the actress for Erica and gave Erica’s plotline to Cora (literally the writers have admitted to doing this, straight down to not changing lines) then lost the actress for Cora, I’m pretty sure they gave that “female archetype” role to Malia next. The writers intended for Erica to be Stiles’s love interest but it kept getting passed around until it landed (somewhat disastrously imo) onto Malia.
Anyway long story short: Teen Wolf Season 1 had a plan, and when losing actors screwed up their plans, they never managed to re-configure their story in a way that was anything nearly so good as what they started out with.
Everyone’s like “those Germans have a word for everything” but English has a word for tricking someone into watching the music video for Rick Astley’s Never Gonna Give You Up.