There seems to be a lot of misinformed commentary going on about the changes to infill rules, and some commentators and developers give the impression that the intention is to reduce the amount of infill overall. But the council's news was clear: "The first part of the review is a District Plan Change (DPC 56), to tighten some key technical rules and standards", but "The second part of the review is a discussion paper ... which suggests the city takes a more strategic approach to where infill and areas of greater housing density be allowed in the future". The intention is to stop the bad and inappropriate developments now, then guide the development of high-quality infill in the best locations.
Perhaps the council hasn't helped itself by cracking down first, without any explicit information about where the infill should be going. Diligent readers of council planning documents (and of WellUrban, of course) will know that the "urban spine" concept is behind all this, with explicit "Areas of Intensification" in Johnsonville, the CBD, Adelaide Rd and Kilbirnie. Some of the documents mention these explicitly, but the general idea is that there's a lot of consultation and analysis to go through before anything is finalised.
Random infill just results in suburbia without gardens, and I don't think anyone (except developers, of course) wants that. Residential density only achieves its social, environmental and urbanistic benefits when it's located where there is mixed use and good public transport. Filling in backyards in the distant hills of Karori or Churton Park, where there'll be two buses a day if you're lucky, will only result in more car-dependent people and more congestion, not more people walking to work and the shops.
The best things to read are the discussion paper (729kB PDF), the plan change documents, and Cr Andy Foster's well-reasoned article from last Friday's Dominion Post.