See, I thought the opposite. After two books of buildup and no particularly major female characters, I was bracing myself for a truly cringeworthy character. Sabetha could easily have fallen into either being Locke-with-tits or way too much of a Mary Sue. It might have been a little unfair of me to think that given how well Jean and Locke are written, but I was prepared to be very, very disappointed. The Sabetha character we got made perfect sense and was very well written. Clever, but not perfect, but not Locke either.
That said, while I was slightly disappointed with RoT, it was mostly because there was no central caper or con. There was no real focus and the book felt like it was doing too many things at once. That said, Lynch was pretty clearly trying to shift gears a little with this book, and I'm willing to cut it a lot of slack for being essentially the middle piece of a series. I'm hoping the next book picks up a little (and doesn't have yet another intro of Locke recuperating from injuries or poisoning. I like how Locke gets beat up a lot, but his whining irritates me as much as it does Jean)