To do well in a hitters' park you still have to be a good hitter, and the same goes for pitchers in pitchers' parks. IMO, in real life they do way too much to counteract ballpark effects-- in 2000 Todd Helton hit .372/.463/.698 (leading the NL in all 3 and 38th all-time in OPS), with 216 hits (1st in NL and t-121st all-time), 59 doubles (1st in NL and most in baseball since 1936), 42 home runs (7th in NL), and 147 RBI (1st in NL and t-53rd all-time). Easily one of the greatest seasons ever, especially by someone not named Ruth, Bonds, or Williams. Because he played in Coors, he finished FIFTH in NL MVP voting that year, with only 1 first-place vote.
So I have no problem with HBD changing it so that it's not functionally impossible for a guy in a hitters' park to win the MVP.