By 'RAW', I mean being able to drive the port by poking at 0x378 in a highly controlled manner. (Not terribly uncommon when the hardware in the article was originally released)
I'd wager the device hanging off the PCIe bus looks very little like a traditional parallel port to the CPU. Notice the modes supported by the device don't mention 'RAW', and a number of reviews bitch about ECP not working.
Just because it is on pcie doesn't mean it isn't just emulating the most frequently used parts of a parallel port.
That will likely suffer from the same drawbacks as 'installing' a parallel port via USB. You still lack the timing precision required to bitbang out many of these protocols.