Hi! I'm currently Y13 taking ClassCiv and intending to carry it on at university next year.
As an A-Level, I've found there's a large variety in the content you learn depending on which units your school offers - e.g. mine does Greek Theatre and Love & Relationships, which are both very literature based and so resemble English Lit more than they do history. Other units such as Politics of the Late Republic or Invention of the Barbarian are (I assume) more history-based.
The best way to get an understanding of the course is through the spec (
here) and looking specifically at the units offered by wherever you hope to study.
I absolutely love ClassCiv, it's by far my favourite of my subjects (others are EngLit and Psychology) as the content is about as fascinating as you can expect when looking at the Greeks and Romans. I do get the impression, however, that as a subject it can often be very dependent on your teachers - mine are excellent, whereas another local school that teaches the same units seems much more lacking (anecdotally), despite across subjects being a higher-achieving school.
It is very much essay-based, so sounds right up your alley (6 essays in 2hrs30 for WOH!). Very content-heavy, however. And no coursework to supplement.
It notoriously is one of the harsher subjects when it comes to the % of students getting As and A*s, particularly compared against a subject like English Literature that will often have double the number of top grades. I believe there's an ongoing complaint about this by the CA, however, so this may be rectified by the time you're sitting exams in the subject.