I definitely agree that we can never go back to doing things exactly as Marston did, nor should we. But in fairness I don't think anyone here wants the book to be transplanted back to the 1940s, just that we want to see concepts, characters and locations from that era utilized more.
I also don't think DC rolls back on developments in favor of Marston all that much, if at all. Azzarello for example ditched the post-Crisis canon, but what it replaced it with kind of flew in the fact of Marston in a lot of ways as well. Rebirth rolled things back to a more Perez-like set up, albeit with some Bronze Age flavor mixed in. But ultimately, I don;t think the post-Marston works are being downplayed that much. Her Silver and Bronze age eras are not regarded by many as being well written overall. And aside from Perez, Rucka and perhaps Jimenez as a third, the rest of her post-Crisis runs aren't regarded as being anything to write home about. Pretty good at best, but nothing memorable and the while Artemis and Cassie came about in those other runs, that's still only two important supporting characters netted over a not brief period of time. Editorial interference plays a part, but then Perez, Rucka and Jimenez has issues with editorial and were still able to produce overall great runs. So their ideas may just be inherently stronger than the others.