It's been a rough season for Salty in Miami. He's essentially been worth about replacement level after his bat has seemingly abandoned him in 2014. He's been fine at home with a .748 OPS, but away he's had only a paltry .611 OPS - oddly enough with a higher walk rate. His defense is about as mediocre as it's been, as well.
The Red Sox decided to go defense-first at catcher and signed the veteran A.J. Pierzynski, long known as a controversial player, to a one-year contract worth about $8 million. While defensively he was perfectly fine and a huge upgrade over Salty's questionable abilities, he simply could not hit. He was worth -0.3 WAR to the Red Sox in 72 games before being flat out released in July. He was picked up by the Cardinals who were desperate for a catcher after All-Star Catcher Yadier Molina went out with injury. He proceeded to be even worse, racking up -0.6 WAR. Pierzynski looked finished after 2013, and he most certainly is now.
So from a straight "do the Red Sox miss Salty" standpoint, it would actually stand to reason that they in fact do, but fortunately the Red Sox have Christian Vazquez. While Vazquez hasn't hit for beans, he's made outstanding plays behind the dish that have made him worth 1.1 WAR in only 55 games according to Baseball-Reference (0.7 WAR according to FanGraphs). David Ross has played at about replacement level as his back-up.
While I can't see the Red Sox really going forward with Christian Vazquez as the number one catcher next year, it appears that they are willing to do so at the cost of offense. Vazquez is as good as advertised and will probably end up being a Gold Glove catcher in the near future. But he's going to top out as an elite back-up for a good team. The Sox need someone like a Russell Martin for at least 2015 and 2016 while they see what top prospect Blake Swihart really is. But the fact is that the Red Sox knew Vazquez's defense would be worth his poor showing at bat, and he may yet improve a bit.
So do the Red Sox miss Salty? Not that horribly yet. Vazquez has been more valuable than Salty this year with his back-stop work. Maybe the Sox were right to let Salty go, but man, they should've just given the job to Vazquez, then.