I’m not sure the vectors question is within the scope of the syllabus.
If you're talking about 14a, all of it was in scope including the linear independence part, but it provided a little taste of the abstract world of uni linear algebra.
The current 4u syllabus IMO has too much physics and mechanics in it and not enough of that abstract maths. If they were ever to reform the syllabus the top priorities I suggest are (extreme and uniformed opinion incoming):
1. Truth tables in proofs. I did this in my discrete maths uni course in a topic called 'Logic' and proof tables was actually really neat to learn since they're so relevant and really helpfil. I guess logic proofs could also be added since they use all the concepts like contrapositive and converse already.
2. Delete SHM and some other mechanics. They're not maths idk why they're here. Physics should take these topics. Ik IB phys has them, why not HSC Phys. In phys these concepts can get the proper depth they deserve, using concepts like work, which isn't covered in maths.
3. Add Further Work on Functions. In uni, many students struggle with concepts like the formal definition of limits, continuity, and differentiability, and doing this in 4u would've been helpful.
4. Expand 3d vectors. Cross-product should get added too. And if they really wanted to be demanding sure linear independence is welcome.
If anyone thinks this is too much to ask (which it kinda is) all these things I mentioned are taught within the span of 3-4 weeks in uni. They're really not that deep.
The point of the new syllabus in 2020 was to get rid of that obsolete archaic high school math (e.g. conics and volumes) and introduce more relevant content that will be expanded in the future should people choose maths in tertiary study. I don't know why they half-assed it with this new syllabus.
EDIT: AND another thing. Get rid of one-to-one, many-to-one etc all those function types from advanced. this will never be used again ever again. instead just use injective, surjective, bijective (along side formal definitions of functions like f: R->R). much easier for everyone.