@SuperSnekFriend@Awoo They didn't learn the important part of the Greek system, have a large random jury with lots of power as a counterbalance to the court's tendency to serve itself in its judgments, instead of a jury that only just votes to convict or not.
Also, iirc, the Roman system didn't originally have lawyers, the practice came out of the fact that wealthy people would often hire someone to speak on their behalf, "as a friend", Cato notably doing so on at least a few occasions.