It comes down to, do you think valuable means most valuable to any team, or most valuable to his team this year. How much value is there in 78 wins? Last I checked you aren't playing in the playoffs so there is no difference between the Orioles and Phillies. As Branch Rickey said to Ralph Kiner, "We finished last with you, we can finish last without you." I think post season/team contribution can be a deciding factor and this year I think Trout and Betts are close enough to consider it. I think 2010 NL is another good example. Votto and Pujols were pretty close, Pujols a slight edge in WAR but they were very close. I think Votto should have won considering he was the cornerstone for the division champs Reds, no way they win the central that year with any random AAA 1B instead of Votto. Other years a guy might be so far ahead he deserves it no matter what. Stanton last year is a good case, hitting 20 more HRs than the next guy is pretty dominant.