Transportblog.co.nz and I don't often disagree, at least on the posts I bother reading at least some of. One thing we do disagree on is the topic of heritage buildings. As you might expect of a history student, I am pretty keen on heritage buildings. The living past, as it were. They're also, typically, classier than more recent crap so that's cool too. Although, if you follow that post closely you'll see that this last point means we perhaps don't disagree as much as I suggest right at the start.
The problem, though, is that a heritage building is, generally, going to be smaller and not necessarily as efficient a user of land as possible. In this sense, you could have a place, say, Ponsonby where people want to live but the only way they can live there is by acquiring a house that someone else already lives in: displacement. This is all very well and good and given that I reciting this back at you, I agree with the idea. You can also see that heritage buildings are probably likely to encourage sprawl (in the context of a sprawling state: if it's an old high density building, as long as it is in good nick, this isn't going to be the case, is it?).
What I am mostly suggesting is that the worth of the buildings as:
a) living history, and
b) aesthetic gods among the fleeting mortals,
means that they should, in general, be kept and the inequitable outcomes that result don't matter so much (hang on, didn't you write several posts on inequity and scholarship?).
Now, I am not suggesting that if you can come up with a good design that preserves the heritage aspect whilst simultaneously changing things substantively that this should be reflexively thrown out. Nor am I suggesting that old = heritage (think of a and b as tests... a heritage building should look good and there should be some historical worth in preservation), and indeed if something is from the 1950s (which in the context of NZ may well mean heritage) but is grotty, and there are plenty of others like it which aren't so grotty, then it's probably for the best that it gets incorporated into something new, moved or replaced. Yes, that implication that as fewer buildings of a particular kind and age exist the closer it becomes to being a heritage building (living history).
Maybe this post is incoherent, maybe it isn't. The point remains, in general heritage buildings should be preserved.