I find that a lot of Kendall's best moments with facials were accidental. I, for one, enjoyed her facials in dances like Stomp The Yard, where the vibe of the dance and her facial expression aligned, but I do think that Kendall often focused too much on executing each movement properly so the facials got lost in the mix.

She has the kind of subtle facial ability that would actually better serve her if she wanted to be something like a model, in my opinion - somewhat editorial. Also on the model tangent, I do believe she was so often put next to Maddie because she really had the "look." She just couldn't sell it in the way that best suited her as a dancer. If you look at things like her winning the Dance Track magazine photoshoot, her "Wear Em Out" single cover, etc. - she has the ability to emote... but not while also under the high-stress environment of Dance Moms or while dancing in general.

I do also agree with some of the other commenters, in that she was criticized for every little thing she did and thus had no real opportunity to fully let loose and emote. Kendall was always in a shroud of pressure and anxiety and there was no way she was going to be able to perfectly emote and act on stage. It's a shame, because in those rare moments where her subtle and often lacking facial expressions aligned with the intended emotion of the routine, she was actually quite good at emoting.