thick blade vs thin blade

The timing doesn't change because of the blade, neither should the stroke as far as I know. What does change is the vibration feedback and often need to get used to being able to push well with a wider ( thicker ) bat.

Depending on properties of the blade, you'll need to adjust some slight angles if speed of the ball changes.

i notice(maybe i'm wrong), chinese penholders use thinner blades, shankhanders use thicker blades.

I played (as in playing around) with a thick 9mm 1ply and hit the edge of the blade more often.  But I think it is psychological, you think you may hit that huge edge, your swing slows down, and then you do hit the edge!

For the blades that I own, it's true that thinner better for looping, thicker better for hitting.
Loop: TBS > Clipper > 1ply
Hit: 1ply > Clipper > TBS

I use a Joola Kool, which has a 10mm thick head. It does need some getting used to. I used to be on a Donic Persson Dotec OFF, which is a lot thinner, when I first shifted to Joola Kool, my first few hours playing, I did get a lot of errors.

The most noticeable difference would be the vibration, or absence of it that is. Helps in positioning blocks as the racket doesn't recoil when blocking hard smashes. Good for smashing too, you can feel the solid hit on the ball. Great sound as well.

But that's just for the Joola Kool. I have another 10mm racket that is all wood, 1 ply Ayous, although feels the same and has almost as little vibration as the Kool, but the sound and feel is very different.

I didn't change any of my strokes from using the thinner blade. As I said, just needed some getting used to. Mid-distance looping is still very effective on these thicker blades.