Taking a look for shortstops in the $4-5 million range, we could compare for example Arky Vaughan 1937 (BA .322) with Ozzie Guillen 1988 (.261).
Looks like a no-brainer no?
But looking at real life and at the performance history in WIS OLs, Vaughan only gets 3-4 hits a season more than Guillen.
Vaughan makes 30 errors, with 2 minus plays and four plus plays for a net loss of 28.
Gullen makes 21 errors and makes 21 plus plays on average with no minus plays. A wash.
Vaughan in real life had an OBP a full 100 points higher than Guillen. But this comes out to 31 more walks. Given the 28 play advantage for Guillen on defense, and the 3 hit advantage for Vaughan on hits, this gives Arky a maybe 6 point lead.
The only real advantage for Vaughan appears to be SLG as we would expect. But they had the same number of doubles - 16 for Guillen and 17 for Vaughan actually. Only only on triples - Vaughan had ten more, and a 5 to zero HR advantage leads one to favor Vaughan.
In other words, it is close and going with the defensive preference is not entirely unreasonable, depending on what the rest of your team is like. If you already have a lot of sluggers, and have a very good fielding 2B as well so that you like the idea of making the middle infield a defensive fortress, you could go with Guillen here it seems to me.
With some positions, like OFs, there are few enough errors, minus or plus plays for 99% of players that it is unlikely that defense will make the kind of difference it can in the IF, but an example like this gives an idea.