See my papers on urban population distribution - they are rather mathematical, but contain reflections on reasons for urban population distributions

Dear Ryan,

In my opinion, densifying one area requires that there is infrastructure of various types: basic water and sewage, lighting, energy, telecommunications, optical cable, transport and road system that supports the overhead.

Best Regards,

Vanessa

As you said within a metropolitan area, presumably sufficient infrastructure and facilities are available and if not then it may be a historical or a derelict area, in that case bringing population could be more difficult as to convince people to invest and build could be hard. If it is an existing area then the local's resistance for more construction could be a matter. If the area lacks a good social reputation or connectivity and access that may be a problem. For building residential complexes or housing estates, the ownership of the lands can cause problem, in case there are small plots, you have to convince a number of owners to create a big parcel for the development. So I think if you narrow it down and select a perspective such as social, real estate, design, planning, you can focus and work in details.  

1. Lack of public consultation - involving the public and businesses in the density decision making process.

2. Lack of political will to carry out such density project.

3. Neighborhoods resistance to change of cityscape

4. Urban decay - hence people and businesses try to avoid the neighborhood

5. Affordability - land and house prices 

All these interesting questions coming out of Deakin!   my compliments!

Market conditions and investment structure

Affordability

Infrastructural inadequacies

Finance (are the residential units going to be leased or owned?)

Distance from amenity

Distance from employment

Security and governance

experience in Australia shows that local public opinion is not a factor, because it is increasingly overcome by council amalgamations and super planning schemes which, rather than applying blanket rezoning, kick nonconforming applications into the black box of tribunal review which usually finds in favour of the development proponent, for reasons best discussed elsewhere.

Large lot zoning in neighborhoods is the biggest problem and for obvious reasons. 

New development or re development? Multi use zone/ residential? High density Metro versus Res/rural sprawl Metro fringe, cheaper land prices and package deals. Position relative to work/family/ interests, availability of land, urban population growth, security, lifestyle expectations, successful re use of space, do people want to change in this direction? all have social and financial impacts of differing degrees, Infrastructure demands. Increased loss of habitat. What will it cost me to live here? What am I prepared to gain/sacrifice for me/my family? for Community/Ecology/ Environment? Local council policies /guidelines pre determine our limits of choice? Do higher density residential communities impact technological advance beneficially /negatively or potentially both? What are the aspirations of Developers and  to what extent does sustainable practice influence their outcomes which ultimately determine our choice of liveable private and active community spaces? How does the appeal process influence reliable positive outcomes and mostly for whom? and how is it measured, if at all?

More questions than answers here to add to a not so simple but complex question Perhaps not all barriers, possibly hurdles?

According to me, beyond technical and suitable solutions, social acceptance of density remains one of the major problems. The literature is often controversial on this point and shows that density may be seen as a possibility for more social interactions, but is also frequently considered as crowding leading to social problems. 

One way to investigate is to dig deep into the microeconomics of urban agglomeration. One of my favorite (amongst the many cited in the linked paper below) is learning- rather the lack of it, hampers residential density.

There is now an emergent debate on whether economic efficiency should be the prime rationale for promoting urban residential density

http://www.nber.org/papers/w9931.pdf

http://switchboard.nrdc.org/blogs/kbenfield/the_man_who_thinks_manhattan_i.html