It's not a bad start. I'm fond of the detailed world, lair, and personality information in the paragraph text of the entry. I'm on board with a lot of people's suggestions in this thread, too!
For me personally, I need to know what other creatures it travels with in the ENCOUNTER BUILDING section -- a return to the "Organization" entry, perhaps. I want to be able to turn to this monster, and, having been inspired, roll some dice and have a complete encounter right there for me.
Maybe something like:
Typical Encounter: Ambush. 2d2 bugbears + 2d3 goblins + 1d2 hobgoblis + 50% wolves
Lair: Camp. Typical encounter * 10
Jhaelen said:
Replace the Alignment line with a list of personality traits!
Personally: lets do both!
Alignment Neutral Evil (greedy, selfish, cruel)
The stat block could probably use some use of color and lines a la the 4e stat blocks to separate information a little better (perhaps traits, actions, and encounter building, and the top, could all be their own boxes) -- I wouldn't mind a stat block that looked a bit more like a table of values and a bit less like a list of things. That's kind of graphic design's department, but it could certainly help.
I also wouldn't mind seeing the encounter building stuff at the top. If you're already familiar with what a bugbear is, that's the stuff you're going to need to reference fast, and if you're NOT familiar with what a bugbear is, it could serve as a bit of a teaser, setting the stage for this creature.