If the Yanks lost A-Rod they'd find someone good to replace him. Someone capable of providing the same glove in the field, possibly someone with a similarly high OBP (perhaps .375) and some power. It wouldn't be too hard to find good quality players who could make the team of Jeter, Sheffield, Matsui and Giambi score tons and tons of runs. A-Rod is and was superfluous on this Yankees team... they don't need that power. They have Jeter (Hall of Famer). They have Giambi (MVP a few years ago). They have Sheffield (consistent 100+ RBI man). They have Matsui (Japanese Babe Ruth). What else do you need? Well, sometimes you need someone who can carry a team on his own back and come up with the hits when it matters. I think you're crazy to say that the Sox could replace Ortiz easily... he's not just an average hitter. I don't know if you can quantify it precisely through OPS or HR or RBI but anyone who has watched the sox play much this year knows that he's a HUGE reason for their success.
Basically, the argument that a DH shouldn't win it is silly. Sure, A-rod is more valuable in the field. Of course he is, its infinity to zero in that category. However, Bill Mueller is also infinity times better than Ortiz in the field, as is Manny. A-Rod is a good fielder, but he's not an irreplacably good fielder. I would be just as happy with Mueller at 3rd defensively. THe argument progresses though, to say that A-rod has saved a fielding position to have a really good DH in the game. Well, the Yankees haven't used that DH spot to make the position worthwhile. Ruben? Tino? c'mon. Having a good fielder who is also a good hitter does not seem to be more valuable to the Yankees as a team than having a good fielding decent hitter (Mueller) at third and an excellent hitting DH.
Sorry, I just don't by it that DH's can't be most valuable players.