WTF at that weapon. I was holding out hope that warrior at least, THE weapon class, would get a badass legendary weapon. That's just uninspiring and likely terrible. Goddammit Blizzard, how do you give the class that's all about weapons a terrible legendary weapon in the expac that's all about weapons? /facepalm
You only want to pull charge minions, deathrattle minions, or end of turn effect minions with that weapon. Anything with a battlecry you don't want to do it, so even in an N'Zoth deck, (with my luck) you'll likely pull N'Zoth when you don't want to. It also doesn't synergize with the warrior quest, since that's taunt minions played, not summoned.
Maybe this could go with that damage your own minions theme that didn't work from last expac? Have that small minion that damages your own stuff, then play this, it pulls Grom,or Rotface, or some other enrage effect minions? I can't see that being worth the cost of this weapon and the potential downsides though.
Why couldn't they just have done something cool, even if it wasn't good? Maybe like, "Hit a minion so hard he joins your team, shuffle that minion into your deck". Or, "5 mana 2/4. Everytime you attack with this weapon, it gains 1 attack". I dunno, anything but that boring POS.