Rogue has needed an effect like this to get meaningful value out of its myriad weapon buffs. While the 5/3 statline is going to make it pretty hard to defend, you'll have plenty of weapon charges to defend it with. Throw a Leeching Poison on your weapon and defending this guy may actually be a breeze.
Buffing durability is way more complicated and easy to fail than just buff atack +X (Attack is a addition, while durability is a multiplication) this may be a good solution. Time and the rest of the set will tell.
Makes Leeching Poison and any other weapon buffs look more viable. It's definitely vulnerable to damage spells, but it should be relatively protected from minion trading given that it allows you to use your weapon to kill of enemy minions. Here's hoping for a new weapon-centric tempo rogue.