Looks like my thread surfaced other classic users who have started to experience similar issues.
Anyway, dropped my phone off at the local blackberry expert centre (singapore) for repairs. Picked it up the next day with the keypad* replaced.
Counter staff told me the technician had no comments.
*the replacement keypad is less rigid in terms of the force required for a keystroke. Not that the build quality is any worse from what I can tell, just less rigid. This is a good thing for me, i'm able to type faster now.. back to my 9900 speed (which I could not achieve with the original keypad my classic shipped with)
**of course whether it's a new type of keypad (some repair replacement set) or some form of tweak to the key rigidity is beyond me.. and I leave it up to your speculation.