Actually it is consequential for the Ash-Dad path to be lovey-dovey since it is remarkably in the "Nice Ashley/Nice Ashley with some fun on the side paths", it is one of the few real (but forbidden) love options for the nice Ashley. Considering that is insinuated several times that Ash´s mom treated her and Bernard badly for years, them growing close (even too close with some variants of Ashley exhibiting Elektra complex) is not that unusual. Seems Eva Kiss read a bit about social triangulation, Elektra Complex and stuff for the game option.It did kind of take some of the fire out of that path, but I would like to see where it goes. Since this happens with the "Nice Ashley" it may prove to be an interesting dynamic trying to keep it under wraps.
I think keeping their love hidden (and 1-2 possible kids) will be part of the end for that stoyline. Maybe Ashley will be married with Erik/Jack or Dave and she and her Dad being secretly together too. Over time their forbidden love grows obviously. At the beginning Ashley is very unsure what to do, later on when she is on a business trip with her boss she inner monologues that she misses Dad and they need to get "reaquainted" as soon as she gets back home.