I don't think sprawling by itself has anything to do with it. The land area of the city has little to do with its ability to plan, especially when so much of that land area is still rural open space, there is just a lack of desire by those in charge to do any planning. I stressed in this thread more than a year ago the need for and value in better planning redeveloping here. Even Downtown, with its wedding cake of stakeholders, people like lakelander have been beating this drum for years to relatively little effect. We can't even get Laura Street where it could easily be, much less Regency Square.
We can't rely on hoping that every developer will be Gateway Jax or else the project might as well be in St. Johns County.
Jacksonville's government is effectively a county government, not a city government. For people that work in planning and development in Florida, it is well known that at the county level of planning, there is very little effort at creating special places. Hence why places like unincorporated Orange, Hillsborough, Broward, Palm Beach Counties and so on are just hodgepodges of sprawl. There is zero sense of place and limited desire/capability to change that. While Jax hasn't succeeded with it's Downtown development planning (which is a whole different story), it doesn't even try to do any real planning outside of Downtown.
Jacksonville has 19 City Council people all covering different districts over a massive land mass. The edge of Council District 12 (SW Side) is closer to the University of Florida than it is to the edge of District 2 (NE Side). The edge of District 11 (Nocatee) is closer to Castillo San Marcos than it is to Regency. The edge of District 14 (Oakleaf) is closer to Camp Blanding/Kingsley Lake than it is to Regency. You get the point. Similarly, at the staff level, you have a Planning Department that is focused on managing growth in a massive sprawling area. They do not have the time or capability to focus on retrofitting existing areas, when they are stretched so thin. With 19 Council people to answer to and so many different neighborhoods to cover, it's difficult to prioritize certain areas over others, so we're just left with a hodgepodge of crap, just like other unincorporated Counties around Florida.
I'm sure there are a lot of ways to resolve this issue, but one low hanging fruit that I've said in other threads before is to create Deputy Planning Directors in each of the 6 CPAC Districts and possibly even divide the junior staffers up to work under each of them. At the staff level, this would at least create a much stronger understanding of certain sides of town and have someone to hold accountable when the ball gets dropped.