Confotro was terrible last year, and the Mets, who are investing in their team, are still moving on from him. Reasonable chance he continues to decline going forward. His career OPS is .824. That’s fine, but it’s nothing special. And there isn’t much of a market for him, so, sure, easy enough to sign.
The higher priority is SP, and, arguably, 2B. The Sox don’t need an ace; they need a solid 2/3 guy. Such pitchers were available in December at reasonable prices, and the FO wasn’t ready or they didn’t bother. Same with 2B. Sure they can trade for one. This FO never minds tacking on 1 or 2 extra young players to get the deal done; easy enough.
Meanwhile, Sheets showed a lot of promise from the left side. He’d be on the first train out in one of the trades.
We’ve seen players like Conforto before; we’ve seen this FO trade for veterans (and it's the same dudes: Hahn and Haber); and we’ve seen young for old exchanges. Generally not pretty.