saw this at the brewhall, datamined from the latest alpha build. The reason it's significant, I think, is it's a green with a tertiary stat, which says something about the design philosophy going into Warlords of Draenor.
Previously Blizzard made it seem like the tertiary stats would be random bonuses, but if they're a major part of our trinkets, then we'll be able to have some control over the type of build we go for. As far as I'm concerned, this is great news. Part of me doubts there will be a trinket like Assurance of Consequence every tier, but having some sort of tertiary trinket available every tier will be fun.
The other thing this tells us is where the level 90 greens are going to be. 516 is a pretty substantial jump from the 430s many players are in when they hit 90 in pandaria. Levelling straight through Pandaria into Warlords will feel like a significant bump in power. Also, if we compare this to the early level 100 weapons we've seen, it looks like our current heroic raiding gear will be good through level 94 or 95, which is about where most people expected.
I'm finding myself very curious how the early content will be balanced. The Timeless Isle was very well done, in that it had content for heroic geared players in 543s, and it had content for fresh 90s in 430s. Blizzard has stated that they want to use the timeless isle model more in their levelling zones, so we should be in for a fun time.