Well, you can't fix everything at once; my guess is Gute had a list of priorities, along with list likely FA targets, and as the day developed he felt the best use of his cap space was those two guys at those two price points.
Could very well be that DL and WR were actually his top two priorities, but as the day went one, he didn't see anyone at the price he was willing to pay, so he moved on down the list to OL and CB, and now has a Plan B to fill those needs in the draft or later in FA - when the feeding frenzy lets up and prices become more reasonable. Or in a trade. Some of those contracts the other day were just crazy high; it gets cheaper as the players come to realize they don't have as many options as they did the first couple of days.
Some of the rest of us have wondered about that too. Gutekunst has never traded out of the 1st altogether, but he has made like about 6 trades up or trades down in his 7 drafts, so I think it's a lot more likely that he'll trade his first rounder than stand pat at 27.
And this could very well be the year he trades out altogether. As you say, pickings look a little slim at #27 this year, and right now we only have 7 picks - plus maybe 1 or 2 comps. He loves going into the draft with lots of extra ammo, so this might be a good year to trade down to the 2nd and grab some Day 3 picks.