First of all, let's look at the big picture for a second and ask ourselves: what happens if Gorsuch's nomination is defeated? The answer is, of course, that Trump will just nominate someone else, and given his abysmal track record for nominating qualified people for a given office, the next guy is likely to be even worse than Gorsuch. Say what you want about Gorsuch--and I'm no big fan of his myself--but by any objective measure he is knowledgable and competent, which is more than one can say about most, if not all, other Trump appointees.
Second of all, the sad fact of the matter is that if we're ever going to successfully impeach Trump and remove him from office, we need Congressional Republicans to get on board. And I could be wrong--this is just my largely uneducated, inexpert, layperson's opinion--but I don't think Congressional Republicans are going to take any such drastic step until this matter of the Supreme Court is settled. So the question we need to be asking ourselves is this: is it worthwhile to block Gorsuch and defeat his nomination if it means delaying impeachment proceedings against Trump indefinitely? Or are we setting ourselves up for a Pyrrhic victory, in which we win the Supreme Court/Gorsuch battle but lose the war on Trump?
As a political moderate, one thing that I can say with absolute certainty is that lowering the number of votes required to approve a Supreme Court justice seems like a really, REALLY bad idea. And Republicans really need to look at the big picture here and realize that they aren't going to be in power forever. If any of them really believe that, especially considering what a clusterf*ck their big electoral victory has turned out to be, then they're even more delusional and out-of-touch than I thought. So if they wouldn't want this rule to changed when Democrats are in power, they shouldn't change it now.
On the other hand, people always get so worked up because the Supreme Court is a lifetime appointment. What people seem to forget is that Supreme Court justices are impeachable, just like presidents and vice presidents and all other "civil officers." Now, you can't just impeach Supreme Court justices because you don't like the decisions they make; they have to engage in conduct unbecoming, and there has to be a trial and due process and all that stuff. But it is possible; they are answerable to the law. So "lifetime appointment" comes with an asterisk and some fine print.
Notice I'm not offering answers, because I don't have any. These are just some thoughts that I've had.