I believe you're wrong in saying that.You are totally wrong. Everything you written is just opposite.
What would be the point of having different keys if they were all the same?
Dude don't you listen to music? You can SO tell the difference if you listen to pieces in different keys!
I don't think you understand what I'm saying. Yes, I know all keys are different in pitch, I'm not stupid! If you listen to a piece in A Major then transpose it down to F Major, you obviously will notice it is lower than it was before. However, the feel of the piece remains intact. Keys (key signatures not notes) are all just a means of placing down notes at relative pitches from eachother imo, then rhythm/dynamics/meter etc are applied to make the piece complete.
Say you have a happy, lively, energetic piece in D major. If you transpose it up to F# Major, you still get a very similar response in feel/emotion because of the way the harmonies and melodies in it are arranged, not based on what key its in. You do notice that it is higher than before but the feel stays the same because the notes still have the same relative distances to eachother as they had before transposition. Just because you may have heard a sad sounding piece in C# minor, doesn't make anything in say G# minor less sad. If all composers had a habit of writing everything sad/nostalgic in A minor, then you'd probably tell me that A minor is a very sad key to write in based on the pieces you've heard in it. I find this quite absurd. That's why I said "I don't get it.".
Tell me, if you took Chopin's Ab Major polonaise and transposed it to A Major, would it feel any less heroic - I don't think so. You might be irritated by it because you've listened to it in it's original key many times, and can hear the pitches are a semitone less than they were before (if you've trained your ear to some degree of 'perfect pitch' recognition by now), but if you're relatively unfamiliar with the piece, you wouldn't really notice (and if you haven't listened to it for a while). I bet after you start listening for a bit, you will even forget it sounds transposed (that's how it is for me anyway). You would probably appreciate the piece the same way other people do, and feel the same emotions. That being only half true, because there is no real way to tell if two people are feeling the same way (you cant exactly prove me wrong for this reason, neither can I you). It would still sound 'herioc'. It wouldn't begin to sound nostalgic, sad, less lively, etc. It is the placement of the notes relative to eachother and what I said before (rhythm, dynamics and so on) that are important. Now, if you were to keep it in Ab Major, and scramble up the notes, that would REALLY alter the feeling you get from it upon taking the music in. Am I more clear in stating my opinion now?