ubiquitin, thanks for the reference. I looked up that OpEd of Feb 18, 2016. Mcconell and Grasley make several arguments. First, legal argument that Art 2 Sec 2 grants the Senate power to provide or withhold consent.
Then, they give a political argument why they should wait, and a significant part of that argument is that Pres Obama’s being a lame duck whose policies were already rejected by voters in 2014. Wiki on 2014 elections uses the word “largest” 4 times for R- gains …. Part of that rejection means – in plain language – Senate is in R- hands and they have power to withhold consent. Then, they go with arguments similar to yours, quoting D-s, including Obama, Biden, Hillary, saying the opposite to what they say now – ein ledavar sof, of course.
I think their argument is not inconsistent with what they have now – R-s had losses in the House, but not in the Senate and, in practical terms, kept ability to grant their consent. And Trump is at the end of his first term, so even the “lame duck” part of the political argument does not apply.
I don’t see that this rises above general self-serving arguments in Congress on both sides. I think the future court packing part of the argument is more interesting.