Freddy Galvis will be 27 in 2017. He has played in 480 major-league games, with 1,777 plate appearances (and 633 minor-league games, with s,631 minor-league plate appearances). This is "inexperienced"? And "wasted development"? Galvis' highest OPS in the minors, at any level, was .727 - in his second year at Reading, a known hitter's park. Two years from now, Galvis will be looking at his age 29 season - and most players do not improve much, if at all, from age 27 to 29. It's highly likely that "he is what he is."
I've seen the argument that Galvis somehow "changed" something in the second half of 2016 - but when I look at his month-to-month splits, that's not what I see:
What I see here is a player who started the season at one level, who went into a two-month slump in June/July, and who then rebounded. Each month realistically represents too little data to be particularly meaningful (about 100 AB per month) - but the overall picture isn't one of a player who suddenly "got better" in the second half - it's a player whose monthly OPS is bouncing around a level that's fairly represented by his seasonal number (.673). The "got better" is an artifact of one month (August) where his OPS was substantially higher than his seasonal (or career) performance level. There's nothing remotely unusual about a player having an atypically productive month.
There is value in a player's being durable, for sure (see Roman Quinn...). But if starting 158 games allows you to generate all of 1.3 WAR...well, that value on a per-game basis "ain't so much," if you will. If your organization has no alternative to a shortstop who can muster only 1.3 WAR in 158 games, one might argue that indicates an organizational failure. I'm repeating myself here, but when I see the Phils ranked 12th (out of 15) in the NL in wins above average from the shortstop position, I can't see Galvis (the incumbent) as having much value. Now, the Phils ranked poorly in wins above average at most positions (they ranked 3rd in CF, and 7th at 2B and C; all other non-pitching positions ranked 12th or worse) - but that doesn't mean that Galvis was OK, because his performance was "better" than Ryan Howard's.
My personal view? We, as fans, need to be willing to let go of our "fan favorite" players, when those players simply aren't good enough. Some of these guys are good stories, and I understand rooting for them - but building a winner involves making hard-headed decisions, without involving the heart - just the head.
