So the bounce sound after click is loud, and left portion of the button is not that responsive.
I brutally moved it a little bit by hand, and it really helps response problem.
And I avoid the loud click sound by pressing the right or the left part of the home button.
After seeing this disassembly video, I realize that how 'flexible' the button is. Not sure if that's possible to adjust it more without disassembling it.
Anyway, I think Tab S's home button is worse than s5. (they all got fingerprint reader),
and I miss the sturdiness of S2, or S3. Even the recent low end products have more steady button (though stiff).