Ideally, a PMTS student should be learning on low angle, groomed terrain... not all mountain terrain. This is true no matter how "advanced" they think they are. Even PMTS coaches and WC racers spend a significant amount of their daily skiing time drilling on easy Green trails. If a skier thinks that would be too boring, they aren't doing the drills right.
For this purpose, a narrow-waisted ski like the Head i.Speed SuperShape would provide faster feedback than an all-mountain ski, as it responds more quickly to tipping movements. This would be a great choice for your daughter's first PMTS ski.
That said, a highly recommended all-mountain ski for those with some PMTS skills is discussed on this thread regarding the Blossom Whiteout (aka Hart Striker):
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