A lot of old "raw" stuff wasn't polished or very well mastered - the quality of the finished product in general wasn't as important back then, once it was a good tune. Sure the boss of Trax for instance was a crook, he didn't care if the production matched up or not, he didn't have to, because the stuff was selling anyway. Nowadays different things are expected, especially with the tools that are readily available to anyone that has a computer. In some ways though the average "producer" now has to be an engineer too, which creates an extra learning curve and perhaps acts as something of a distraction from the whole process or making a tune.

Put an old Chicago acid house track against for instance a newer acid track by Jesper Dahlback, and you'll notice the obvious difference - yet they could be both raw in their own way, just one is far more polished and modern sounding than the other, that said I think Dahlback is one of the few who has carried on the acid torch and done it well.

You take early Trax, Dance Mania as Crime mentioned, even 808 State stuff - they sound rough as hell but far more rewarding to listen to. If I play something old that lacks in volume or is a bit rough, I just adjust the eqs or crank it up to fit in smoothly. A few years ago I got records on a label called Robox from Austria - really low recordings, and not too well mastered, but by hell were they records I remembered a lot more than something silky smooth and polished. Likewise, today if I hear something raw or not as pristinely produced I'll still get it if I like the tune - there's still not too many records I hear where the production is rubbish, most stuff is ok.

I think the one thing that differentiates "raw" of yesterday to a lot of tracks of today is the minimum amount of elements used in a track. With muli tracking being more prevalant today, I think it is inevitable that production standards, eq/compression etc. would need to be better.