I guess this one would be a matter of user experience, in-universe. Early on, our heroes would not bother with creating detailed settings, but they would learn by doing. And the holodeck would also learn to cater for their exact tastes, no longer having to go for generic and bland.
We did get a detailed setting from the get-go - the location shoot for "Encounter at Farpoint" - so it's apparently not a technology issue. While the technology might not be new, our specific TNG heroes would be new to it, so it would only be natural for the "quality" to take a plunge once the ship was off the hands of the original engineers and test crews... And then slowly recover to the location shoot level.