For Atwood, I'd say it's nowhere near her best. I found it readable, but forgettable. God, I feel awful saying that. She's one of my favourite authors. I absolutely love love love The Tempest too, so maybe that didn't help.
The Margaret Atwood books I have read so far have been some of the best I have ever read, so expected great things from Hag Seed, found it disappointing and quite dull. I sympathise with your point of view op, I felt the same about this book and kind of speed read the second half, but should have abandoned it, didn't because I'm trying to get through the "50 book challenge"