I think he'll hit 40, of course 50 is a stretch, but it isn't impossible. I also think WAR misses a little bit here. Prince Fielder may not be a top 5 1B because of his abysmal defense, but at the end of the day I think he's still top 10 at the general position of 'hitter.' I don't think his down 2013 is a trend, it's just a bad season. His 2012 was very good, offensively speaking. The dude OBPs .400 more often than not, he has monster power, and unlike most other guys with his kind of power he walks almost as much as or more than he strikes out. By far his best similarity match on BBR at this point is Eddie Murray - after his age 29 season, Murray had 5 more good years left with the bat.
Nobody can predict the future, and everybody can see that Prince is fat, which at the very least isn't great for his knees. But if you humor me for a minute and pretend you can accept 2013 as a fluke, can anybody come up with 10 better hitters in the game? Based on offense alone, just the bat, and the legs if you want. I've got:
Cabrera
Trout
Votto
And that's it. And then I've got a few guys I would consider roughly equivalent:
Cano
Goldschmidt
McCutcheon
Harper (because of his age and room for improvement)
Who am I missing? And if I'm not missing a LOT of guys, how can you not see how this is a potentially extremely valuable piece for the Rangers? At the end of the day, WAR can't work perfectly for lineup analysis because offense isn't purely additive. A guy with power and OBP like Prince makes everyone around him in the lineup better - better pitches to hit, more chances with runners on base and in scoring position, higher runs/times on base ratios... At the end of the day, I just can't believe that good Prince is only worth 3-4 wins.