Re: I spot a trend here ..
The current/next presidents appointment to the supreme court will probably have more impact than most of their their first term decisions.
In terms of lasting impact, yes. First-term presidents have two choices: go big, which means squandering most of your political capital fighting entrenched interests (for good or ill); or press for smaller goals that mostly make only relatively minor adjustments.
There are some exceptions, of course, like the Violent Crime Control act Clinton now famously says he regrets signing; that was in his first term, and contributed greatly to the outrageous incarceration state. And a first-term president can certainly do some damage, for example by continuing to prosecute an enormously expensive and long-running war, or by pulling out of that war and letting another nation collapse. (I never said it was possible to avoid doing damage.) But significant durable change is hard for a president to achieve, particularly in the first term (because except for Polk they're always playing it a little safe in anticipation of running again), and particularly these days when it's so easy to mobilize opinion against anything.
You're also correct that the SCOTUS nominations are the #1 thing the GOP leadership is sorry to lose out on. Their real worry now are in-doubt Congressional seats (and recapturing their own unruly party, of course). This looks to be a year that will turn out the vote.