Handmaid's Tale TV series is good, but misses a big opportunity

I am, rather belatedly as usual, currently watching the Hulu TV series version of Margaret Atwood's book, The Handmaid's Tale, and trying to decide what I think about it.
It is such a beloved and iconic book that many other people are clearly also having problems coming to terms with it. The consensus seems to be that it is generally well done - as I suppose it should be: Ms. Atwood has apparently been integrally involved in the production - but there are certain beefs that keep recurring:

• The TV series seems to be set in pretty much the present day, while the book, written in 1985 and set in an unspecified near future, was deliberately vague about the timescale. I guess that's not really a big deal.
• The book never mentions the protagonist Offred's real name, even if the real names of some of the other characters ARE mentioned. This seems deliberate on Ms. Atwood's part. The series, on the other hand, makes no bones about identifying her as June, presumably with Atwood's permission and blessing. Is this important? Probably not as much as some commentators are suggesting.
• In the book, the state of Gilead is inherently racist as well as sexist, to the extent that "the children of Ham" had been segregated and relocated en masse to some unspecified "Homeland". In the TV series, several of the characters are black, including, crucially, some of the Handmaids themselves, suggesting that the system is happy to allow mixed-race children to be born to the high-ranking white supremacist families running the state, which rings somewhat false to me. I assume the decision to substitute in some black actors was made in order to avoid the allegations of racism and white-washing so prevalent in the film and TV industry these days. I do understand that argument, but it seems unfortunate in this particular case, where the whiteness of Gilead is such an important tenet of the state's philosophy, and I am frankly surprised that Atwood sanctioned the decision.
• The head of the household to which Offred has been assigned, Frederick, or The Commander, is described in the book as older, silver-haired, paunchy and mustachioed, and the choice of a young, fit, dark-haired Joseph Fiennes with a full beard seems a rather perverse one. Presumably, the producers were looking to inject some sex appeal into the dour society of Gilead, where sex appeal is just no longer relevant. Margaret?
• Ditto the Commander's wife, Serena Joy.
• The character Ofglen is made into a handsome gay woman in the TV series, not the grumpy, dowdy character in the books, and she is tortured and mutilated for her "gender treachery" in carrying on relations with a Martha, rather than being taken away for her connections to the rebellion, as in the book. Gratuitous titillation? Why not just stick to the book.
• In the "salvaging" scene in the book, it is the radicalized Ofglen who is the first, and the most strident, to attack the rapist. In the series, however, it is Offred herself who takes this role, which seems somewhat out of character.

There are other complaints as well, some of which I agree with and some not so much. But I think that in general the series does a good job of visually portraying a beloved dystopian novel.
The other big thing I am not so happy with, though, is the whole idea of adding in new plot lines, such as the Mexican deal that appears out of nowhere in Episode 6. Now, I think this is probably to do with the strictures of the modern TV series. I have a suspicion that someone told the producers around this time that ratings were good and a whole new series was needed, and hence a need to string the existing plot out and add in new material while the economics were still good. That's a really bad reason to alter the plot, and I am saddened that Margaret Atwood did not have the balls to specify at the get-go that the plot should follow the book, and that it would take just one series of ten episodes to achieve that.
Story arcs are important, after all. But, instead, it looks like we will end up with yet another bloated, shapeless series that is just as long as the paying audience can stomach it and no more. What a shame.