Old Hockenheim was interesting because it had those long bent "straights" which pierced the lonely, dense forests. It was punctuated with a few chicanes, and it had the stadium section which allowed cars to catch up to each other. There were two typical passing zones: the run down to the first (Jim Clark) chicane, and the hard left hairpin (Sachs Kurve) into the stadium. But the fastest cars typically outran everyone else to the point where passing chances usually faded away as the laps wound down.
The track was also too narrow to allow for close racing; the front straight was the only place where cars might even attempt to go three-wide, but the marbles and the fact it was the second and third consecutive right-handers kind of kept away most passing from the view of the front straight. Lastly, it has almost no elevation changes nor much natural terrain; the forest saved it from being totally sterile. Even in its time, races at Hockenheim were usually regarded as a bit of a snoozer in the shape of Circuit de Catalunya and Hungaroring; a few occasional spicy events, it usually not all that interesting. But I also think the media saw it as a bland reaction to the disappearance of Nürburgring from the rotation.
The new circuit adds more passing opportunities, and some more challenges. I feel there are also far too many paved run-off areas which inspires close racing at the expense of driver tactics. But I suppose it was in response to the Old Layout...there certainly wasn't much along the one-mile stretches.
Admittedly, I like the new one over the old, though I get nostalgic for the tree-lined straights. Monza fills that void...but for how much longer? That said, I'm totally okay with giving the track back to nature, which the public can enjoy, rather than to selling it to private development, even if it means there will be no vestiges of the track in the next 30-50 years.