I believe there's already an effect, it's just too minute until you hit some wpf sweet spot or other. I know a few other regular duelists and I noticed a reduction in block speed post-patch, and it might be related to the wpf nerf. I'm not sure.
All I know is that in the past, I didn't have to commit to a block- I could switch it around and settle on the correct one at the last millisecond. This allowed us to match each feint with a block. These days, I pretty much have to see which swing is an actual swing and commit to it.
Of course, this could also be a result of people getting better at high-speed deep feints, but I don't know. We'd need access to pre-patch conditions to test it.
Asking to have block related to WPF .. it's like asking to make the aiming with a sword using wpf .. completely non-sense !
Much like how a high weapon proficiency archer or high horse archery has arrows that occasionally 'home' in on targets, I believe that a higher melee weapon proficiency provides instances where the wrong swing is bent into a right one.
I used to have 227 wpf pre-patch, and I distinctly recall time when I'd swing a miss and the blade would just snap to my opponent on its own.
Currently, with 172 wpf, I see this happen every now and then, too. It's a very odd swing that looks like an instant change- watch for it. A lot of times, people think it's a chamber, but it's not. It's your wpf working for you!