On my 25s, when new, I use the tip of my finger to flick out the blade a bit. The blade will not fully open, just get it off the detent and out about 1/3 - 1/2 way. Then I push against the thumb stud again and open the blade fully like normal.
Once the ceramic ball wears a ramp into and out of the detent hole and the "track" it will ride in/on the blade, it will get easier.
I have always opened 25s that way, almost two years later, and even a medium-forceful flick of the thumb tip against the stud will not fling the blade fully open and slam against the stop pin. It, sometimes, will open all the way and barely click into place. But typically it just gets it out there so I can open it up without any thumb tip pain, and it works like a charm.
With their excellent tolerances, it is a struggle at first but it will get better as things seat, the ramp wears and the lube gets spread around/thins out a bit.
But it is well worth it. I have many knives that open easier, but the 25 design is so stout when open that I have forgotten how they can be a pain at first to open. I simply don't care, as it is a most excellent knife.
I currently have three of them, two with micarta inlays (one left-handed and one right-handed) and a standard handled one, which was my first CRK ever. It will easily last you until they put you into the ground, so hang in there and you'll soon see what we have come to love about these knives as well.