You know why we have all those Latin phrases in law? Because the last person to try to simplify the legal code as a basis for laws in all countries to the degree you're talking about was the Byzantine Emperor Justinian. Hence why we call our current framework of Common Law the Justinian Code.
Obviously, it didn't eliminate the need for lawyers, but it was quite a revolution in making the legal profession more accessible to talented young people. Up until that point, a lawyer really had to have the level of expertise of the statesmen who made the law in the first place. That meant legal representation was really something only the very powerful could have; after the Justinian code, it still took a lot of training but you didn't need to BE a lawmaker to navigate the law.
The trouble with what you're saying, though, is that what you want is to simplify the legal code way further than as far as Justinian got, and you're talking about a lifetime of reform at the hands of people who have gone down as some of the best legal minds in history. You want to knock the Justinian reforms out of the water and make it look like babytown frolicks.
And prove me wrong! That'd be quite an amazing achievement and if you think you can do it, the world will pretty much be your oyster after that. But law is an inherently complicated thing when you've got pretty much every interaction between every human being raising ethical questions about what the law should and should not be. If you've ever been around children and gotten a taste of what happens when people defend themselves on grounds of a set of rules that literally nobody else has agreed to, you should be getting a feel for what a nightmare it is to get a group of adult people to play by the same set of rules.