Tarah and Danny beat them by almost 15 points in 2016. Also they only won this year by 6, not a high margin considering Tarah and Danny weren't perfect and were coming off major injury. They shouldn't be thinking that they are unbeatable at Nationals. If they can't land those jumps a clean program with less difficulty will be able to do itUnless they somehow end up getting beaten at U.S. Nationals. Which I don't think would happen - but weirder things have happened.
Best of luck to the Knierims. I was a bit surprised at this news - I was under the impression that Alexa and Chris would never leave Delilah - but I think this change will be for the better. I think Aljona should help them with packaging their programs and nailing their elements better.