http://www.gameinformer.com/b/features/archive/2014/12/03/stare-into-the-dark-below-new-details-on-the-destiny-expansion.aspx?PostPageIndex=1

Some of them seem fairly significant, like allowing you to upgrade an Exotic piece of armor with Xur so that it will fit with the level cap jump from 30 to 32 in the expansion. I'm glad I found out, because I'm going to start material hoarding to be able to do that with my three different yellow armor pieces right away, and it looks like buying Exotic Shards for 7 Strange Coin off Xur will be the easiest way (sure wish they would give me Exotic Shards for the 4 or 5 non-class or duplicate Exotic armors I've scrapped in the past, though...). Also seems like they're making reputation rank levels count for something more (Commendations?) although it's not clear to me exactly how that economy is going to work from this write up.

Aside from that, good preview of the content for those as curious as me.