@Dustin58, guests do have a star rating so I'm not sure I really understand what you're getting at. As hosts, we rate our guests based on a star rating out of 5 for cleanliness, communication and observation of house rules. Then we decide whether we would recommend them or not. You can also flag guests to report them for very bad behaviour. In response to your statement "If I was able to let everyone know about the bad guest who complains about fees after checkout, wouldn't everyone want to avoid renting to that guest" Yes, we would. That is why it is important to leave an honest review of your guests.
Unfortunately, we can't control how our guests rate us, we can only do our best to make their stay as great as possible. I honestly haven't shared your experiences of "working our butts off for guests and doing everything right, and then being threatened or slammed by a low star rating review" or "have a hundred stories about guests that we did everything for, and then they stuck us with a low star review". And if someone does leave an unfair review, you can always leave a public response to it - most guests will see this in perspective, especially if the majority of your reviews are positive. If it's really dishonest and inaccurate, you can ask Airbnb to have it removed.
In response to "let us adjust our booking requirements to only accept guests with a certain rating" - there are ways you can do this. Either turn Instant Book off so that you can pick and choose who you accept, or set your IB settings so that only guests with good ratings can Instant Book.
I also think that the way the reviews are set up so that you can't see a guest's review until you leave your own review is actually an excellent system as it avoids tit for tat. Imagine if you left a poor review for a guest before they left their review - then they could retaliate by leaving you a bad review as well. And everyone would leave it until the last minute to leave a review so they could read the other one first! Also, two weeks is hardly a small window of time to leave a review.
If you don't like the system, maybe AirBnB is just not for you...