But there's soooo many pets skills to use and I was thinking of trying out this build when my R/E ascends to R/W just for fun. And I wouldn't want to see ANet's attempt at a useful companion go to waste. [vs. all these other games where the pet is just there to 'look cool']
stats:
10+2 Beast Mastery
9+1 Expertise
7+1 Marksmanship [to wield the bare minimum req. max dmg bow]
10 tactics
Tiger's Fury
Ferocious Strike {E} ?? Not sure if it's elite but someone said it was.
Maiming Strike
Scavenger's Strike
Predator's Pounce
Call of Haste
Charm Animal
Watch Yourself!
Very pet centered. It deals the damage it needs to and behaves kind of like the "Offensive Tank" mentioned in the Guild Wars Preorder Manual.
Needs high powered attacks: Ferocious Strike and Call of Haste means you'll be dealing dmg, gaining energy, and adrenaline for Watch Yourself! Tiger's Fury makes yourself less useless at range ^_^ The other skills deal extra dmg as well as a variety of effects. All of which are more efficient than any warrior or caster can possibly keep up with.
A snare / speed buff skill: Maiming Strike combines well with Call of Haste as both an attack speed buff, movement buff, and snare. 3 effects for 2 skills is hot. If the enemy's not moving, it's still +17 dmg for low energy. No weapon snare can compete with that kind of energy/dmg.
Survival: Not just a self heal, Predator's pounce will be for those occasions your poor pet gets duped into an AoE spell and helps it live for that much longer. It can be substituted for Comfort Animal for massive fights like 8v8. In 4v4, I think Predator's Pounce helps it do more dmg. Ferocious strike keeps the energy going so you can do this skill many times when needed. Watch Yourself!! lets your whole team know you're there for them as well as your pet!

Some weaknesses I wouldn't need to hear of are Conditions and Hexes. There is nothing this build can do to combat those things. And there is no need to for the most part.
This build plays off the general thought: Pets are useless, ignore them and focus fire on enemy pcs instead. Placing the pet as the last target after the enemy's last warrior goes down. lol...
From what I can tell with this build: You and pet are both dealing a lot more dmg then would be realized at first. Both you and your companion have attack buffs that can render an enemy dead without some level of attention.
I was wondering if there's a way to augment this build without changing the secondary. This is a team build, not a soloist.