The Santana deal is interesting, because it's more than I thought he'd get. And I'd rather have signed him to that deal than Hosmer. So, Hosmer at 4-6 years for $20M+ per just sounds terrible. I've been against Hosmer from the start, but Santana signing for a more similar $/yr than expected has refocused it for me.
Martinez's bat fits really well on this team, but there's currently no place for him to play. And, I think moving JBJ or Hanley will result in a significant loss of value, since we'd be selling low on either. Is it worth it to overpay for him to be primarily a DH? Maybe. But this team is going to be competitive in 2018 regardless of the offseason moves. How successful they'll be will hinge largely on whether/how much a lot of the players currently on the roster bounce back (Price, Porcello, Bogaerts, Betts, Ramirez, Bradley) or improve (Benintendi, Devers, Rodriguez). If that doesn't go in the general direction hoped, having Martinez signed long term could look really bad a couple years from now with only a wild card game or two to show for it - as opposed to having JBJ as an asset and Hanley's money off the books. Of course, without him, we'd be left wondering what could've been with him... And he's the "home run" signing available. I don't envy DD this offseason.