Actually, when I got mine it was the other way around. The plain edge blade was the harder of the two to open.

With that said, I've found that on most Waves, Charges, ect the plain blade is the one that is typically easier to open. I believe this is due to most people using the plain blade more often, causing it to wear in a bit and become smoother.

The nice thing about my newer wave though, is that it uses standard security torx bits (instead of the special five pin security-torx that my Charge and other use). Therefore, the blade tension can be easily adjusted. In fact, the whole tool can be taken apart and polished to make it operate much smoother. I do this to most of my Leathermans in order to make the pliers easily open-able one handed (as they tend to come very stiff). Just keep in mind this will most likely void your warranty and can mess up the tool if not done correctly.