Innovative for asymmetric multiplayer?
Though, you are right. AvP from 1999 already had asymmetric multiplayer and still is the better game overall except for graphics and multiplayer support (number of players).
AvP definitely had higher quality and less (no) bugs than PHG.
AvP 2 and 3 were inferior to AvP 1, imo.
Innovative for audio design, maybe? Listening to your foe is crucial in PHG.
In the end, it doesn’t matter. I still like PHG alot and have played it much more than many other games. Only Illfonic is holding back PHG instead of fully supporting it.