i dont know all the technical terms, but i can give you my impressions..
a lot of the newer stuff that sounds bad, is due to the compression that you mentioned. when mixed, it seems that they try to pack as many layers on layers of sound, to where it ends up just being to 'bright' and busy. there tends to be a lot of harsh effects and restructering of the sounds, that on a good speaker, just end up becoming confusing and hard to listen to.
on older recordings, the flaws often come up due to simply poor recordings. especially some of the older guitar driven stuff.. the guitar can sound so enhanced and way forward, while the rest of the band and the vocals are muddy and left in the rear. good example is led zepplin. great band, but not well recorded. also, the old KISS stuff on the casablanca label is not very good.
you will know pretty quick when listening, if it is a good recording or not. there is a big difference. but dont let this deture you. there are much more good cd's than bad.
bigjohn
