A new station would surely put Parkway out of the picture. Not many 'locals' use it with I'd say at least 75% of its pax going to/from LTN airport.
There currently is an old station with an overgrown platform on the midland main line, called Chiltern Green. You can see it to the right going towards Harpenden.
Maybe this could make a comeback, although think it only has 1 overgrown platform left.