question about the usefulness of past papers

If a paper is intended to cover the whole of the syllabus one way or another, wouldn't i know basically the rough idea of every single question that will come up by doing about 4 past papers?
Should everyone just get 100%

Hey Angelo, hmm, not really. It depends on what subject but exams are about applied knowledge and demonstrating the understanding of the subject / theories etc. Plus syllabus change.

Although you are right that it almost certainly helps - doing practice and past papers will almost certainly help you. Many people just wouldn't both to work through four past papers.

If a paper is intended to cover the whole of the syllabus one way or another, wouldn't i know basically the rough idea of every single question that will come up by doing about 4 past papers?
Should everyone just get 100%

Short answer: No.

Long answer: Doing past papers is without a doubt very helpful (you should aim to do all the past papers available before the exam). However, it is not a substitute for revision. You need to revise the entire specification because whilst a lot is recycled between exam papers, there will always be questions that are new.

indeed, but the new questions arent exactly new... they are just questions that haven't been used in a long time.

...there are always new questions.

new questions or not, they are always differently worded... every paper is meant to cover the whole syllabus so there can't be any ENTIRELY new questions

Of course there can! Have you ever even done an exam paper?!

well yes... all i saw was questions that i already answered in mock papers

Trust me. It is absolute lunacy to claim that there are no new questions.