As much as everyone hates lawyers, without them we'd be back in the middle ages and less fortunate people would always be punished while more fortunate will get off. It would be bad...
Well, probably. In all conciebable systems (even in our own), some get favoured over others. The question is who gets favoured, and in what degree. Let's see:
1) In a system like the Greek one, in which each individual was supposed to plead his own case, the ones who are more educated would be benefited. This is becouse the better educated would probably know the law better and would know to express themselves better and more convincingly than the least educated ones (on avrege, of course). As, usually, in most societies, the better educated are richer than the average person (even if they aren't necesarly THE RICHEST persons), this system favours could be accused of, inderectly, favouring the wealthy.
2) In a system like the one in place during the Middle Ages, where disputes where solved by duels, the strongests tend to get benefited. If weapons are involved in the duels, those who can afford the best weapons will ussually win their case. And even if no weapons are involved, if a system like this is established in a society like the one that existed in the Middle Ages, the rich might probably win more often, as they would be, on avrege, better trained, better fed and in better shape than the avrege peasant. Thus, this system favours, indirectly, the ones that are in the highest ranks in society.
3) In a system where dispute are resolved by, let's say, dropping a coin into the air, no group gets benefited
a priori. (Trial by ordeal, during the middle Ages, was a form of this). But, in this case, it's quite likely that the one who wins the case is the one who was wrong (as it is also the case with system number two). And if he isn't, it's just because by chance.
4) In a system like our own, the ones who are "right" tend to get their right reparation, at least in a greater degree than in systems 2) and 3) (Not neccesarly than in system number one). But it is clear, at least according to me, that this systems favours the wealthy (those who can pay the better lawyers) EVEN MORE DIRECTLY than systems one, two and three.
Of course, no matter which system is adopted, those in the highest ranks of society would bprobably try to use their influence to get certain advantages. But the degree in which this occurs would vary according to the system adopted.
But, the question is, could a system like number one be apt for a modern society? I don't think so, as we tend to hiper-specialization, and it is unlikely that an avrege person, even a highly cultivated one, would know
all areas of the law. He may defend himself reasonably well on a crimminal matter, but he would have trouble in pleading a case against the government over, let's say, certain external tariffs applied to his business.
But maybe, if advocacy hadn't appeared in the Roman era, we might have two separate systems: in criminal and most civil (divorces, family problems, damage of property, etc) cases , each persons pleads his own case
personaly. On more complexes issues, in which money or complexes regulations are involved, lawyers are required.