Santana would be my choice, too, all things considered. But I don't have the history of signing "best available" like Dombrowski does.
I actually don't want JD Martinez - although I see the appeal - because I want to keep all three outfielders as they are. They're part of what kept our pitching so good with terrific defense. The worst glove out there was Benintendi, and in no way should he be moved.
And putting Martinez at 1B/DH? I love the consistent logic there. Suggest moving Devers to first and people are all up in arms. "Moving Devers to first is crazy!!! Let's sign JD Martinez and put him at first. A much better idea!! He has NEVER played the infield in his entire professional career!! And probably hasn't fielded a ground ball since high school!!! He's the perfect fit!!"
I'm all for moving an inexperienced guy to first, but I think having some infield experience helps. I also hate 6+ year megadeals for players over 30. Unless there is an early opt out.
On an unrelated note, I will say, I do love the MLBTR prediction that the Sox sign Bryan Shaw...