I don't know where you're getting your information about it being based on audio fingerprinting, but I'm pretty sure it would take a lot longer than it did to audio fingerprint my 21,000~ songs quite quickly and found 6000 that needed to be uploaded.
Do you think wave analysis has to "listen" to each song, in real time, to completion, in order to function? Well that is not the case: It's just a few seconds in most cases. So assuming a 20,000 song library, with zero purchased through iTunes store and none ineligible, that would only take approx. 14-16 hours to match.
I also gave an easy to test scenario that proves it is using wave analysis. Never mind the fact that by your logic I could copy one song 20,000 times, change the metadata of all the copies to different songs, and have an instant library thanks to iTunes Match.
For those who care, or want to try themselves, during the beta when I removed all metadata from a test iTunes library and compared matching times with and without metadata they were the same. They matched the same too, of course.
Ideally, they should let you (after the main match is done):
Right click a song
Select "Manual Match" or something.
Give you a selection of songs it thinks it is a match for.
Let you either select it or just change it to upload your own version.
Also, drop down the artwork and meta data while you are at it.
Too bad that will never happen.
That is a good idea, though you are also probably correct that it won't happen (the part about allowing you to force an upload should be fine).
I like the idea of bringing up a selection of songs that it can match to. Of course I can see the record labels saying that that is essentially letting you choose a song other than the one you presumably "own."
I have no proof of this only a hunch, but I believe Apple had to agree to not use user metadata for matching whatsoever in order to get the record companies to agree to allowing Match to exist in the way that it does. So I don't see Match ever allowing user metadata to override wave analysis, or even to help it.
What I would really like to know is how many songs the average iTunes library contains. I have a feeling it is far less than the 25k (non-purchased) tracks allowed. by iTunes Match. If so there is a lot of noise being generated that will not really affect most users. A cursory check of my friends and family found not one person with over 10k songs, let alone 25k. Maybe I travel in circles of people that don't listen to much music. I "thought" I did but compared to the huge numbers I am seeing in Match threads apparently I do not.
Michael