@Ward1 It's not fair- there are tons of things about the review system that need changing.
But reviews shouldn't be written on the basis of what the other party might write. They should just be factual. If a guest wasn't respectful of a shared space, other hosts who have shared spaces need to know that.
As hosts, I think we need to let the small annoyances go- we're dealing with a whole range of human behaviors and not everyone is going to do everything exactly to our liking. So you might have a guest who needs a lot of hand-holding, can't seem to figure out how to work anything by themselves, even with written instructions that they read. Okay, they're a little challenged. But every time you help them, they say thank you, they express their appreciation. In a case like that, I wouldn't mention that they needed more instruction and help than most guests. But if it was obvious that they never even bothered to read the instructions, phoned and texted at all hours, expecting me to run right over and help them out and never said thank you, then I'd write "this guest was quite demanding as far as not bothering to read the house manual as to how the appliances and door locks worked, sending numerous messages, some quite late at night, asking for help with these things".
And since you can respond to a review, if you're taken by surprise by a less-than-fair guest review, when you've given them a good one- "I'm sorry that XXX was so bothered by these things she mentions here in the review- I was unaware that they were a problem for her during her stay, as no mention was made of them at the time. I tried to let the small annoyances I experienced with her not affect my review of her, as she was, for the most part, a decent guest."
We can't control what guests write in their reviews. We don't know if, asyou say, they're going to write a great review or a petty, nit-picking one. I never think about what a guest might write when composing my reviews, I just review the guest honestly, according to my experience with them while they were staying.
And Ward- guests often give 4* reviews because Airbnb leads them to think that this is a good rating. It's not that they're trying to tank your stats- if they were trying to do that, they'd give a 1-3* review. You need to let guests know how the star ratings work from the host's end, because Airbnb doesn't.