Looks like Blizzard has posted up their thoughts on the design decisions when it comes to Icecrown. The lengthy interview posted today goes over some interesting bits about Icecrown, items, and encounters. There isn't a lot new in it, but it's still worth a read.

What sorts of new loot and item abilities will we see in Icecrown?

Greg: There are three main sources of loot for Icecrown: the bosses themselves, the Emblem of Frost badge vendors, and a new faction, the Ashen Verdict, that will provide suitable rewards as well, particularly at the Exalted level.

As far as the items themselves go, we want them to feel epic. In addition to having favorable optimization, we also want to try a lot of experiments to make the items feel cool and unique. We are going to try to do a lot of weapon procs, for instance, which is something we haven't done much since the original World of Warcraft.

Read more at the Icecrown Interview page at the official site.