I don't think its the only factor at play here, but the answer to your question is yes, yes it is.
I tend to agree. I think the AL East makes matters even worse. NY, Boston, and Tampa Bay are probably good enough to win any other division, and one of them won't even make the playoffs. Toronto could probably win a division or two and Baltimore would probably be in the wildcard hunt if they played in the NL West.
I mean as good as the Phillies were last year, if they had played in the AL East, they would have finished 4th or 5th in the division and not even sniffed the playoffs. Same with this year.
Fortunately for the Phillies, baseball is a huge game of streaks and chances. Note that dominant teams in basketball and football can win 80% of their games or better. Not so in baseball. The Yankees have the best record in baseball and have only won 64% of their games (which would translate to a 52 win team in basketball). Most division leaders, however, are playing 58% ball, which would translate to 47 wins in the NBA, or basically what the Walker/Pierce teams won in their best year.
So yes, the NL does suck, but that doesn't preclude them from winning a World Series if they get hot (and lucky) at the right time.