He's expendable due to the progression of Savoie. If you rather keep Holloway, then by all means replace him with Carter instead.
I don't get this rational at all. Prospects are just that, prospects. As one starts to play well, that doesn't all of a sudden make one "expendable". You can never know for sure who is going to turn out to be a legitimate NHL. You keep them and hope as many turn out as possible.
As for this deal, its brutal. As mentioned above, no Oilers fan would even consider Holloway alone for Kuemper, let alone add a 1st. Also, Savoie and Holloway aren't on the same level at all. Savoie has been progressing nicely, but Holloway has the pedigree and production thus far.