For question one, you could discuss many different factors. For example, our system is in fact impartial, as the judge acts as an unbiased figure, whose main role is to over-see the two parties and their legal representation, in order to make sure everything goes according to plan. The judge never interferes with the proceedings of trial, and this is an adverse advantage of the adversary system because it allows the flow of court proceedings to maintain consistency.
Then, when talking about time efficiency, you can argue that indeed, many commitments are met, as this system of government allows the flow of court to run smoothly.... etc
In this question, I would also tend to discuss the disadvantages, and where flaws are present within these particular arguments. For example, if the judge remains impartial, many questions could not be responded to in a more efficient manner as if the judge were allowed to comment on the diverse proceedings. Etc
For question 2, I would state the numerous weaknesses involved with using the legal system... Costly, formal, too broad or not specific enough... Etc. Then I would Explain why the use of mediation is actually a better method... Fast, inexpensive, informal, no need for legal representation... Etc.
I'm sure you can explain everything I have just mentioned in more detail.
EDIT: Just realised you have already had your SAC