think some producers get a little lazy and fall back on percussion to provide the energy and rhythem rather than having an interesting structure or interacting samples that provide the groove.

i usually think of percussion as an after thought to pad a track out a little, rather than the essence of the tune. i sometimes get the impression that some techno producers would be unable to write anything if they didnt have access to basic percursive samples
Ummm

Percussion. n striking of one thing against another.
Percussion Instrument, musical instrument played by being struck, such as drum or cymbals.

Percussion as an afterthought.

Umm, no percussion, no kickdrums, no hi-hats, no punch to the rhythm.

Percussion is the heartbeat to the body of techno.

(Well, what most of us call techno, ie techno for dancing)