Easy solution. When a pet is reduced to 0 HP, it's knocked unconscious, but as long as the PC is alive, it pops back to 1 HP at the end of the encounter. And if it's adjacent to you, it takes no damage from area or close attacks.
I don't mean to pick on you, RangerWickett, and I know you mean well, but I don't think this is an easy solution. I don't think it's an easy solution when, a day after the release of this new-to-core element of the game, people are already suggesting house rules to fix certain aspects. Isn't this supposed to be a finished product? Aren't the folks at WotC professional game designers?
I'm paying WotC to come up with rules and themes and classes and powers so I don't have to. If I have to house-rule magic item rarity, rare magic items, themes, and everything else... then what am I paying WotC for?
I'm normally a huge supporter of 4e, but I really think the quality has been slipping lately. If all the themes were as crappy as Animal Master, I would understand, but when you put it side-by-side with Order Adept and nobody says, "Hang on a second," I really have to wonder what is going on.
Really, my only guess is that WotC blatantly doesn't care about balance anymore, about avoiding setting up 'trap' choices for players. They seem content to just poop out an on-rails class or theme and then move on to the next one. If it doesn't work, oh well. And if it works too well, errata!
Either that, or they need to shake up their staffing a bit, because I really think somebody dropped the ball here.