pretty much all biblical scholars today agree that many of the major books of the bible have already been rewritten
When the Dead Sea Scrolls were found, there was something like an 800 year gap between its age and the previously oldest-known Bible. What it showed is that there was basically no difference between that and more-recent versions that we had. Similarly, the Gospel writings traveled east and west, and not only do we have copies close to when they were first written, but they also don't show editorial differences despite the huge geographic difference. The Bible has not been re-written or edited. Certainly we have a few differences in how the original Hebrew and Greek was translated to English, be we can learn those languages. The Bible currently is as it originally was. There exists Books which are a better fit to the anonymous/questionable/edited problems you note, and they weren't included in the cannon.
our better understanding of morality
That's debatable.
slavery, for example, is just appalling by today's standards, and forces Christian apologists today to bend over backwards to find a way to make these verses have some unobvious meaning.
It's noted a few times in the Old Testament that God basically made a compromise with Jewish Law due to sin and the hardness of our hearts. Imagine if it were the year 1200 and God declared that slavery must be completely abolished. Would society change overnight, or would it say 'eh, screw that'? And so God's law on slavery was similar enough to surrounding cultures that it could be accepted by the Jews, but at the same time much better. Not perfect (perfect society is given to us in Genesis 1-3), but better. And along with that, Jews had the ability to improve upon those Laws. Slavery, specifically, did see a positive evolution throughout the Bible's timeline.
You can argue that it's all convoluted or that the explanation is complicated, but that's just what we do with any book, analyze them to the Nth degree to best realize the meaning. Additionally, it's history, and why would you want to edit out history? We wouldn't delete mentions of WWII just because some folks were monsters, would we?
to remove all the places where evil is being perpetrated in the name of some supposedly "all good" being.
The Bible is clear to mention this, too, that not only does the devil try and use the Bible for evil purposes, but that we should test our Christian leaders to know that they're truly from the Lord. Understanding that evil sometimes wears a well-meaning mask is a pretty important lesson to learn. It would be a disservice to remove that lesson.
The laws that nobody follows or likes today because they are either nonsense or outright evil would simply not exist in the new text.
What you're suggesting is to replace morals with values. So in the year 1400 the Bible says "Slavery is a-ok!" and today the Bible would say "Abortion is cool and adultery is a lifestyle choice!" With no more morals, the Bible would get changed to just whatever happens to be popular in the moment. And when evil gets to be the next author of the updated Biblical value list, I guess we just roll with it?
Nobody would be stoned for minor offenses, for example.
Haven't noticed many stonings in my neighborhood lately. This is due to proper exegesis of the Bible.
pretzel-twisting mental acrobatics
I took a 400-level Shakespeare class in college once. He was a complicated writer and it was all a bunch of pretzel-twisting acrobatics. Should we re-write him more simply, too? Same with any other complicated book. You're complaining about the Bible for the same things you would praise any other book for including. You're effectively asking for Game of Thrones to be dumbed-down because you have to think about it too much and it's too complicated, and therefore it's terrible and should be re-written.
I feel like if God really does exists, he would be telling at least one of you to do this
Your hubris is showing.