Living in the Moneyball era, stats are god. Sabermetrics inundate and pervade scouting. That's not necessarily a bad thing. However, a purely statistical approach has its flaws. Although the strict sabermetrician will disagree, I believe there are aspects to anything, including baseball, that haven't yet been quantified, if they even can. In this case, and now my writing may start to make sense considering the title, I don't believe sabermetrics completely explain the effect of power, specifically homerun power, on a player's value, measured here in WAR. That is because on fangraphs, WAR, for the offensive side of the equation, uses wRAA, which directly uses wOBA. wOBA strictly uses numbers, defining the result of each plate appearance in a game, in its calculation.
Therefore, it does not use two major aspects of power that I believe clearly exist in the game of baseball. The first, I believe has more of an effect. A hitter with more power will be feared more, and therefore will get pitched to more carefully. That in turn should allow a hitter with patience to walk more and be more selective, getting better pitches to hit. The second I believe has less of an effect, and that is protection. If Michael Bourn is protecting Albert Pujols, Albert Pujols won't get any good pitches to hit, which will increase his OBP slightly, but give him less chances to affect the game with a big hit, usually one worth extra bases. If Matt Holliday is instead protecting Albert, he will hypothetically get more pitches to hit. How much this actually happens is up to debate and I suspect this particular effect is small.
I wrote these two long paragraphs to point out that I'm not ignoring these factors nor should they be ignored. However, my analysis will be purely statistical.
For whatever the reason, the 30 HR plateau seems to be popular these days. Looking at the Pirates minor leagues, arguments could probably made that Cunningham, Curry, and Dickerson could one day hit 30 HR's in the major leagues if you dream big. Josh Bell, who has yet to take professional AB definitely has that power potential but is years away. However, after that is stark and clear that the Pirates lack power hitting depth in their minor league system, at least 30 HR power hitting depth. How big a deal is that?
For some reason, and I've surely been guilty, people seem to think 30 HR hitters grow on trees. Let's simply look at the numbers. Via Fangraphs.
30 HR Hitters - 23
Highest WAR with less 30 HRs - 8.0, 4th in MLB, Dustin Pedroia (21 HR)
Players with less 30 HRs with more than 5 WAR - 15 out of 29 (51.7%)
Teams without a 30 HR hitter - 13 out of 30 (43.3%)