So far, Live is pretty good in guessing the tempo of .wav files, i.e. how many beats they consist of. But sometimes (many times?) it has problems with that, and you have to manually adjust the tempo settings and save the (.asd) file. Time consuming at least.
ACIDized files come with tempo info ready right out of the box, through a proprietary tag within the .wav file. If Live could read this - like ACID does - it would open the Live loop library by many gigabytes...
and what a 'competitive upgrade' that would be...