half plates are basically just for alignment of switches to stabs. they really don't do much else.
more than the plate material, lubing makes the biggest difference in sound. i was amazed at the difference with the 1st batch i lubed (non-dampened, of course).
- switch films can help with some loose fitting housings/tops, can also change the sound some
- how much empty space is in a case will affect the sound (big, roomy case or something that has very little "open air" inside the case)
- plate material can effect the sound as well, steel being the ping-iest. all metals will carry the sound/ping more than other materials
- caps will also affect the sound, usually, the thicker the cap, the lower the sound. and PBT is usually slightly deeper than ABS given the same profile & thickness of caps.
- dampened switches, other than the obvious, they really do a good job of being "quiet", even more so than the old dampened alps. and i am talking about 2 of the 3 silenced MX i've seen, the cherry/aliaz (gateron)/gateron (with 3 bumpers at bottom of stem, single up top) as well as the outemu/hbheroinbob silenced variant with the single/larger (and removable) bumper. the latter, being very close to the original alps dampening as far as how it's constructed, though the rubber bumper is more pronouned in this MX variant. i don't have any of the ones that use the rubber bands like alpaca's.