Aztec Kid,
I would prefer what you call "nuisance warnings" at 25,000ft, which at least tell you the system still works, to a nerd fudzing around with the 'logic' so much, that the next time a real EGPWS warning gets inhibited, because "it looked like a nuisance warning".
Keep It Simple, Stupid!
So far, it doesn't sound as if we're too far down that road yet, from what you're saying.
CJ