All zips of this sort, not just the Gore ones, have to be lubed. It's not peculiar to them. The Spidi suit I had was the same and similarly rubbish too by the sounds if it.
For me personally, a more robust simpler even if less waterproof zip would be better.
I have replaced the zip pull with a key ring ring, and it works fine but on a suit costing what klim charge I think I am entitled to whinge a bit if it does not work first time all the time and without breaking.
