Her entire career has been built on trying to follow the same template Twain masterfully did in the late 90's. But I do think Taylor had more of a reputation in the country scene/Nashville than Shania ever did. Shania was always an outsider in Nashville, and country music purists always detested her, so she had nothing to lose by doing more pop oriented material (thanks of course to her then husband Robert "Mutt" Lange of course). Taylor, on the other hand, has built the entire foundation of her career in Nashville, first as a songwriter and then as an actualized artist. So possibly alienating that section of her base is a potentially risky move.
Taylor's success is really only concentrated in America though. Though she's toured Europe and other parts of the world, she's NEVER had the same following internationally that she has in the US/Canada. I wonder if her more pop leanings are an attempt to make her a more global star.
Shania at her peak was a GLOBAL star. Her 1997 album, Come On Over, isn't just classified as the best selling country album ever, it's the best selling album for a FEMALE ARTIST EVER, in both the US AND WORLDWIDE.