I know I'm going against what everybody else is saying, but I honestly don't think 176 is too short. If you're skiing 95% park, you want something that's quicker side to side, more manuverable, and lighter... and most narrow-waist 176s (such as ar5s) are all about that. The only benefit I see with longer skis in the park is a bigger landing platform, but then you have to compromise the swing weight.
I'm 6'2" 175lbs and I ski 176 AR5s in the park. I have 187s for everywhere else... but when I'm in the park, 176 is perfect. Go for it...