I'm not a great authority on Legal Studies so take my post with a grain of salt. This is how I approached the subject, but I didn't score as well as others.
Evaluate and critically evaluate commands are asking you for strengths and weaknesses. It would be a waste of writing, time, or allocation of marks to give your opinion after an evaluate question. If your question was "Critically evaluate the doctrine of precedent" and it was worth, say, 4 marks, I'd allocate 2 marks to strengths (2 strengths, 1 mark per strength), and the same for weaknesses. The mark breakdown would be strange if they wanted your opinion. 1 mark opinion, 3 marks on evaluation? Doesn't make sense.
Well, I suppose you don't have to specifically say "to an x extent" - but why would you imply something when you can say it explicitly? Examiners hate to guess. In fact, you should assume your examiners are mean. So mean, that if you make them guess, they'll just guess that you don't know the answer and you won't earn the marks. Protip: be as clear as you possibly can.