NS will always be NS. It doesn't make sense for us to change into something we aren't, but it does make a ton of sense for us to take influences of good parts of the internet. Its like when your favorite musician all of a sudden gets into another musician you like - and influences start to show up in their music.
We absolutely understand the importance of forevermore maintaining the 'latest' ordering. Even if we did go to the point as to offer hot, top rated, controversial or 'happy' views - latest post would never, ever, ever, ever be ditched.
Our main thing we got from Reddit is the math they use to sort stuff. On the back end of the internet there is some pretty complicated mathematics, but if you borrow formulas from other smart people then we all don't need to go back to get our masters in Math at University to make sure NS is still cool. The ranking stuff we have learned has been like magic, actually getting a much more accurate picture of what is good and what isn't.
As to why we haven't added up/down votes to posts within the forum yet, there are two reasons. The first is performance, until very recently we didn't have a way to render that many voting buttons quickly on one page. Paul solved that with the latest updates to the homepage.
The second is just what you're all talking about - the possible drastic change to the culture of Newschoolers isn't something we plan on taking lightly.
Up/Down posts could change everything. It could change drastically how Karma is calculated, drastically your opinion of other members, and it offers a massive amount of possibilities for sorting options for the forums. Like our media galleries, we could easily add other methods to sort/look at forums for those who don't want to sort through as much stuff, or those who just want to check out a bit of NS gold without digging. It would actually give threads accurate ratings in regards to the content of the whole thread vs. just the opinion of OP.
Now, we do definitely plan to put this into a forum overhaul plan. However, before we commit 100%, we're going to take a long look at the functionality and culture behind the NS forums. We'd implement this only if we can come up with a cool way to add to the experience, and add to the overall culture of the place.
TL;DR: We can do this, and we can make it absolutely awesome. Just will not rush into it.
No-poles, free souls.