That's a pretty good definition of transparency, as far as "transparency" is concerned. I wouldn't completely agree with that.
From my perspective (as an audio engineer), I tend to think of gain reduction / dynamic range compression (without any artifacts) as "transparent compression", and things that add a lot of noise, distortion, or change the envelope (attack or sustain characteristics), or change the tone of the incoming audio in any audible way would be the antithesis of "transparent" to me.
Interesting stuff. Obviously trasnparent means different things to different people - it is a slightly annoying and non-specific term. In terms of Phil's, much better, description of transparent, I clearly do not like transparent compression - and as Electric Catfish says - I want to hear the effect compression is having or I would not want to use one. I still feel that it may or may not be a crutch depending on how you use it - I feel there are things I could not do without it. i don't think I am using it to compensate for technique - maybe I'll feel differently in a few years when I am a more experienced player.