The two are completely unrelated. It's great that we have great offensive production from shortstop. That doesn't mean we have to accept near-zero production from the least (or second-least) important position player.
We've been over this a thousand times and all seem to agree on this principle: there is an inverse relationship between the difficulty of a defensive position and the expected offensive production from that position. Doesn't mean you have to get low production from a hard position; DOES mean you HAVE to get production from an easy position.
Honestly what's so hard about that?
So if Trea was light hitting and Zimm mashed so that the sum offensive output was the same as what we currently have you'd be satisfied? Sorry but I DO find it hard to follow that logic.
It's a lot easier to upgrade the bat at first base since practically any warm body can play the position and the league is awash in players that would be an upgrade if not now, as non-contenders start dealing. Heck, Lind may be an upgrade against RHP.