My review: "In certain respects this is an attractive book, perhaps even an impressive one..."
The publisher's proposed endorsement by me: "An impressive book..."
There are other instances of the same thing: my hedges and caveats are washed away, leaving a hell of a blurb.
I know this is how it works -- there's no point expecting a publisher to put anything but high praise on the back cover. I'll be hoping for the same thing when my next one comes out next year.
Still, should I worry at all about having this sort of thing appear on a back cover when in fact the book had some significant flaws? I suppose it's enough that I apparently have enough stature in the field now to be a source for blurbs.
Don't let them put your name on it if you don't actually think it is an impressive book. Tell them not to use it, or provide with them with an alternative that you CAN endorse and offer to let them use that.