Abso-fuckin-lutely not!
I'm 5'9" 165 lbs.  I do freeride and XC cycling every other part of the year that I can't ski.
I ride the Karmas in a 177, and I wish I would have gotten them in a 172.
They're killer skis.  Great all-mountain, super-stable, they bust through the crud, and when mounted at or near the FS line they mach down the hill riding switch.
However... they're STIFF, not Head Mojo stiff, but damn close.  You could ride 177's a scream all over the hill on groomers, but if you want to get into some dicey terrain you're going to want to be able to keep them under control.  At your weight I'd suggest the 169, unless you're going to fill out some, then I'd go for the 172.
Cheers!
-Nathan