@Kelly149 If this were a brand new host, I'd go easy and make suggestions in private feedback. But you say this host has almost 20 listings and 300 reviews.
Sorry, but this isn't a 5* place to me as you describe it. It certainly isn't a "boutique hotel". And you say that the location and high demand dates are such that the host will be successful simply from existing. So a 4* review isn't going to tank his listing. And he isn't a host who has one listing, like you, or me, who might take things so personally, he's a real estate investor.
If a previous guest had mentioned many of the things you have here, would you have booked this listing? I suspect not. So it seems to me that you owe it to future guests to be honest. How else will a host think it's important to change things that need changing, or even know that guests were displeased?
I would send private feedback about the things that would have made your stay (and that of future guests) more comfortable, like more towel hooks, some shelving in the bathroom, more than one towel each (I've always thought a bath towel, a hand towel, and a washcloth are kind of basic, and I actually give my guests 2 bath towels, because women often like to wrap one around their wet hair, especially if it's long), and maybe even the blaring night light and insufficient drapes, as it's highly likely he's never been in there at night to realize how nasty it is. You don't have to suggest those things as if you're a superior host giving him the benefit of your experience, just say it like any guest would- "We would have appreciated...." and "You may not realize because you've never tried to sleep in there at night, but that security light...."
In the public review, I would say how friendly and communicative the host was, and anything else positive, like that it was clean (and smooth check-in, maybe?) but say that there were things that should have been mentioned in the listing, like the difficult parking, the construction all around (and if that was noisy, for sure speak to that), the shared hallway, etc. Not that that would be a reason not to book, just that they should be disclosed, so guests can decide for themselves if that would an issue for them. As far as the construction work inside that will always make the place look grimy, maybe a "not a lot of attention to the tile finish work in the bathroom construction, so the "boutique hotel" description doesn't seem quite accurate, but it didn't really affect our stay".
So the things I'm saying I'd mention in private feedback are all things the host can take on board and change if he wishes to (although, as Andrew says his experience was when he did just that, the host paid no attention to it and the guests were still mentioning it in reviews a year later) whereas the things in the public review are things he can't do anything about, but should have disclosed in the listing description .
