If you're sweating so much you feel you need pitzips, you're wearing too much clothing. Either take off the shell or wear something thinner underneath.
Seriously, if you're so hot that you have to completely open up a jacket, you're overwhelming the system, and you're obviously warm enough to not need the shell. I've found that people, including myself, tend to overdress for conditions.
If you're hiking in 30*F rain, shove the under and shell sleeves up around your elbows, unzip the chest as you can.