Actually, it will "hurt" you when you park your 75's and replace them with 737-7/8/9's.. The pay difference is between the those airplanes is $5.25 (12th yr 73-9 vs. 75 FO as of 1 Jan 2013) and it's even worse for the 73-7/8 ($5.98).

So knowing that the mission of the 75's will be replaced by a different, yet more capable airframe- why would DALPA & ALPA National have allowed this lower payscale?

When 2015 rolls around, those 75's left will be paying $154.50 while your 73-9 will pay $148.93. Southwest currently pays $151.

While I realize that payscales are just one part of a contract, and that there are also many other compensation factors to add into.. there is no denying that the 737NG's are a 757 replacement.