Jim Edmonds
Here's a bit of a wild card. Yes, I think Jim Edmonds would make an excellent hitting coach. Some fans tire of his rigamaroles during broadcasts about players he works with and speaks to, but his in-game analysis shows that he has a great baseball mind. Edmonds is able to dissect at-bats like few others can, and he could potentially translate that into the dugout.
I have heard no whispers about Jim Edmonds desiring to be a coach, but he would make a darn good one. Edmonds was primarily known for his defense as a player, but he retired with a career batting average of .293, an OPS of .903, and he hit 393 home runs across 17 seasons in the majors. He was also a part of the 2006 World Series squad.
Edmonds has been in broadcasting since March of 2013 when he was hired to be an analyst in a pre-game show. He's been a color commentator/analyst for 10 years now.
Edmonds hasn't shown much interest in becoming a coach at any level in baseball, but he did once express a desire to become an owner of a team one day. He doesn't want full ownership, but partial ownership could still be in the cards for the former Cardinal outfielder.
While Jim Edmonds is technically an inside hire, this one feels different. His unique perspective as a hitter who experienced plenty of success while playing is reminiscent of Mark McGwire to an extent, and McGwire was one of the best hitting coaches the team has had since 2010.
Jim Edmonds moving from the broadcast booth to the dugout would be a huge leap, but it's not out of the realm of possibilities. I, for one, would be curious to see what effect he would have on the dugout and players immediately. He's still young(ish) at 54, but he's been in and around baseball for so long that he has a fantastic knowledge base to draw from.