Britney Spears is trailing her Circus tour around Europe currently. The show had a start in the US in the spring and will be returning there in August, then on again to Oz. Reports are that the showmanship is great: which is, after all, what it's all really about.
Given the (not) strength of Britney Spears' voice in the first place and her background as a dancer, it was always going to be heavy on the dancing and rather a lot of the vocals on a backing track or two.
But then why not? If that's what the general public wants to see, why on earth shouldn't they have what they're prepared to pay out real money for?