The hope, of course, is that any given supreme court justice will be impartial and do his damnedest to clarify the law without any partisanship. The fear, of course, is that the minute you confirm a justice he's gonna become an ideological tempest. I seriously doubt the Republicans expected John Roberts to uphold Obamacare based on interstate commerce clauses but here we are.
As far as the filibuster, there are a few thoughts:
(1) it's gonna die anyway, might as well make the Republicans responsible
(2) If the Trump presidency becomes more visibly illegitimate, the odds of the Republicans going to the mattresses for its supreme court pick becomes less likely
(3) if they do get it, whoever has the balls gets to take another run at FDR-style court packing
(4) what's the point of having filibuster power if you're afraid that you'll lose it by using it
(5) Ruling to destroy the filibuster might work out about as well as ruling to approve Trumpcare so let's see if the Republicans have the stones
It's parliamentary warfare, for sure. However, the Democratic argument that if Merrick Garland didn't get confirmed because Obama only had a year left in office, sure as shit Gorsuch doesn't get a vote because Trump was installed by the Russians. This is pretty much the very definition of "politics."