I had a 42-minute connection yesterday on FAI-SEA-DTW (made possible by extra hour from Daylight Savings Time change) and made it without having to run (although I just missed my C+ boarding zone). Was fortunate that both flights were in concourse A, but having to go from A1 to A13 was still quite a hike. As in most cases, I'd look at the possible backup options and if they are acceptable to you before deciding to go with a shorter connection. It looks like SEA-SNA flight can sometimes use Satellite S gates which can make connections more challenging as you will need to take train out to S gates.