I lived in Carina Heights for the last 5ish years in 3 different streets and only moved out 6 months ago, the reason its the fastest selling is two fold.
1. They recently changed the development laws for the part of carina heights to mirror the other part, so a lot of big blocks that have been bought up by locals who have been expecting this change are now being sold off to developers
2. Big block sizes. You can easily pack 4 town houses on most of the blocks, or what most have been doing is buying the street-street blocks and squeezing in 8.
So while its "the fastest selling" the reason for that is because people are buying scummy old houses, bull dozing them and selling 4-8 town houses on that block (have a look at the current sale stock, town houses galore.)
The reason I left was that there was way too much construction, just in my little street alone (which was a quiet street) there was easily 6 town house development projects, the block next door to me had just been bought by a developer & the 16 town house development across the road was making parking a b***.
oh yeah, that's the other thing, parking in most of those streets is currently f***ked. You can do an 8x 2 storey 3br town house development and you only have to provide 8x 1 car garages or car parks. Given that the vast majority of the renters in the area are students or young people & the public transport is not that great (10+ minute walk up a big hill to get to a bus stop.. everyone drives) the majority are 2+ car households. So basically remove 5x family homes, put in 40 units with 80+ cars within 30 metres of each other and suddenly you've got a battle royale for parking with all the original owners used to a quiet little street bitching and moaning about how impossible it is to park there.
tl;dr: it is the fastest selling because its the current sweet spot for cheap land / developable block sizes without having to line up multiple block purchases...
If you can get a house there, maybe. personally I wouldn't touch any of the town houses there (having lived in everything ranging from the bottom end $300k-ish to the $550k+ "executive" nicely fitted ones) the quality is all pretty mediocre.
I'll make a generic comment regarding the above:
If the hold period is 10+ years [ 20 is better than 10] , then construction and population growth isn't a bad thing, provided the necessary infrastructure can support it [ and even of it cant, it will eventually catch up]. Construction and pop growth has too many benefits to list- some of them include gentrification [ i.e.new stuff looks better and is better quality than 50 year old run downs], attracts a more productive [ and well off] class of resident, and all this in turn attracts govt infrastructure spend due to population growth [eventually].
If, on the other hand, the hold period is short term[ say 1-2 years], then the increase in stock levels will not bode well for your sale. This is where people get into trouble- they take an asset like real estate and try to flip it in a short time. This isn't hong kong, shanghai, mumbai, or Rio where you can get 30% gains year on year [ could easily go the other way too). This is little old Brisbane where they still take a public holiday so that you can go see the sheep and cows at the Ekka.
My conclusion: hold for as long as you can and you shall reap the rewards [ as with most property in most suburbs]. Just make sure the fundamentals are right before purchase - things like transport options, distance to employment centers, healthcare, shopping, safety, attractiveness, marketability etc.
If your view is long term, I would not worry too much about new development. Developers build because they think they can make $$$- supply and demand stuff. If that were not true, then I assure you no development would be going on ( definitely not in a capitalist democratic society).