Specialist is quite arithmetic heavy, whereas methods has always been the logical one and likes to concern itself more with the steps involved in solving a problem rather than algebra (hence the name). If you look at exam 2 part Bs for both subjects you'd see what I mean. For methods there would always be 3/4 questions involving real-life scenarios, whereas for specialist it'd be mostly pure mathematical ones (giving you a complex equation, asking you to find roots, sketching graphs, finding volumes, etc). This is perhaps because the curriculum Specialist does not allow for much real-life applications. (I've never seen imaginary numbers used in real-life except in circuits.)

IIRC the 2015 methods exam 1 was actually quite similar to a specialist exam, requiring the students to differentiate extensively and often involving a wide range of expressions. Which is probably why getting a 30% equated to a C on exam 1 last year. It's warranted, as most students taking methods are not as equiped to deal with arithmetic-heavy questions than specialist ones, especially under a timed condition, and it's never been the purpose of the subject Mathematical Methods.

Sorry for the long read, but I think this is why VCAA decided to change the direction it's going with Methods. And I reckon it'd be a welcomed change.